Newton had a fun way to approximate general roots...
#21
Ok, I didn't understand almost anything, but what the heck.

In case anyone is interested: A function that can be used to calculate the n-te root from a basis. Certainly still room for improvement when it comes to larger numbers, in terms of clean formatting.

Code: (Select All)
'N-te Wurzel berechnen - 15. Sept. 2022
'sqrtn(x, n) = x ^ (1 / n)

Option _Explicit

Declare Function Nte_Wurzel(n As Double, x As Double) As Double

Dim As Double n, x

Print
Input "Wurzelexponent: ", n
Input "Radikand      : ", x

Print
Print Using "Die ##.# Wurzel aus ###.# ist: ##.###"; n, x, Nte_Wurzel(n, x)

End

Function Nte_Wurzel (n As Double, x As Double)

  Dim wurzelx As Double

  wurzelx = x ^ (1 / n)
  Nte_Wurzel = wurzelx
End Function

[Image: n-te-Wurzel2022-09-15.jpg]
Reply
#22
I think I saw that formula when I was search around online. I couldn't use it, because I have not yet created a decimal power algorithm in my string math routines. For instance input 2 as the root and 16 as the number: The equation 1 / 2 = .5. Raising x ^.5 is not in my routines yet.

I may need to find a method to calculate decimal powers soon, but that method would have to be based on */+-. No logs.

Thanks for posting this, as it is great for small numbers. Very efficient!

Pete
Reply
#23
(09-15-2022, 09:14 PM)Pete Wrote: I think I saw that formula when I was search around online. I couldn't use it, because I have not yet created a decimal power algorithm in my string math routines. For instance  input 2 as the root and 16 as the number: The equation 1 / 2 = .5. Raising x ^.5 is not in my routines yet.

I may need to find a method to calculate decimal powers soon, but that method would have to be based on */+-. No logs.

Thanks for posting this, as it is great for small numbers. Very efficient!

Pete

The formula comes from here: Quick Basic: Mathematische Funktionen

I entered the 16th root of base 2. The result is correct - of course, if you check it, you get the usual inaccuracy: 1.99... instead of 2.

[Image: n-te-Wurzel-2-2022-09-15.jpg]
Reply
#24
Wait, the link has an error - but I don't know why. I have no problems.

Ok, a screenshot:
[Image: n-te-Screenshot-Seite2022-09-15.jpg]
Reply
#25
Well back to working with Euler approximations. So based on his work, I put together what I think is a pretty cool way to get decimal roots like 7^2.3, 8 ^.7, etc. calculated without using logs.

So if this works, it can be adopted to use with string math routines I have already made.

DECIMAL POWERS ROUTINE

Code: (Select All)
WIDTH 120, 42
_SCREENMOVE 0, 0
DO
    INPUT "Number: "; num
    LINE INPUT "Power: "; power$
    IF INSTR(power$, ".") THEN
        t = VAL(MID$(power$, INSTR(power$, ".")))
        power$ = MID$(power$, 1, INSTR(power$, ".") - 1)

        a = 1
        b = num
        x = 0
        y = 1

        highc = b
        lowc = a
        highz = 1

        DO
            t1 = a * b
            c = SQR(t1)
            t1 = x + y
            z = t1 / 2
            IF z = t THEN EXIT DO
            IF z > t THEN
                highz = z: highc = c
            ELSEIF z < t THEN
                lowz = z: lowc = c
            END IF
            PRINT a, b, highc, lowc, z, highz, lowz
            a = highc: b = lowc
            x = highz: y = lowz
        LOOP
        IF LEN(power$) THEN
            a = num ^ VAL(power$) * a
        END IF
        PRINT "Results = "; a
    ELSE
        PRINT "Results = "; num ^ VAL(power$)
    END IF
    PRINT
LOOP


Pete
Reply
#26
Okay, here is a combo of decimal powers and general roots using the formula ...
Code: (Select All)
x ^ (1 / n)


...provided by @Kernelpanic in a previous post. Too tired tonight to test out much tonight, but I know it will be littered with rounding errors like cube root of 125 = 4.999something.

Code: (Select All)
WIDTH 170, 42
_SCREENMOVE 0, 0
DIM SHARED limit&&, betatest%
limit&& = 32
betatest% = 0
DO
    PRINT "Press 1 for general roots or 2 for decimal powers: ";
    DO
        _LIMIT 30
        k$ = INKEY$
        IF LEN(k$) THEN
            IF k$ = CHR$(27) THEN SYSTEM
            IF k$ = "1" OR k$ = "2" THEN EXIT DO
        END IF
    LOOP
    PRINT k$: PRINT

    SELECT CASE k$
        CASE "1"
            LINE INPUT "Number: "; num$
            LINE INPUT "Root:   "; root$
            temp$ = sm_div$("1", root$)
            PRINT sm_pow$(num$, temp$)
            PRINT
        CASE "2"
            LINE INPUT "Number: "; num$
            LINE INPUT "Power: "; power$
            PRINT sm_pow$(num$, power$)
            PRINT
    END SELECT
LOOP

SUB sm_greater_lesser (stringmatha$, stringmathb$, gl%)
    compa$ = stringmatha$: compb$ = stringmathb$ ' So original variables do not get changed.
    DO
        WHILE -1 ' Falx loop.
            IF gl% = 2 THEN EXIT WHILE ' For bypassing sign and decimal adjustments when only positive non-decimal numbers are being evaluated.
            ' Remove trailing zeros after a decimal point.
            IF INSTR(compa$, ".") THEN
                DO UNTIL RIGHT$(compa$, 1) <> "0" AND RIGHT$(compa$, 1) <> "." AND RIGHT$(compa$, 1) <> "-"
                    compa$ = MID$(compa$, 1, LEN(compa$) - 1)
                LOOP
            END IF
            IF INSTR(compb$, ".") THEN
                DO UNTIL RIGHT$(compb$, 1) <> "0" AND RIGHT$(compb$, 1) <> "." AND RIGHT$(compb$, 1) <> "-"
                    compb$ = MID$(compb$, 1, LEN(compb$) - 1)
                LOOP
            END IF

            IF MID$(compa$, 1, 2) = "-0" OR compa$ = "" OR compa$ = "-" THEN compa$ = "0"
            IF MID$(compb$, 1, 2) = "-0" OR compb$ = "" OR compb$ = "-" THEN compb$ = "0"

            ' A - and +
            j% = 0: k% = 0
            IF LEFT$(compa$, 1) = "-" THEN j% = -1
            IF LEFT$(compb$, 1) = "-" THEN k% = -1
            IF k% = 0 AND j% THEN gl% = -1: EXIT DO
            IF j% = 0 AND k% THEN gl% = 1: EXIT DO

            j&& = INSTR(compa$, ".")
            k&& = INSTR(compb$, ".")

            ' A starting decimal and non-decimal.
            IF j&& = 0 AND k&& = 1 THEN
                IF compa$ = "0" THEN gl% = -1 ELSE gl% = 1
                EXIT DO
            END IF
            IF k&& = 0 AND j&& = 1 THEN
                IF compb$ = "0" THEN gl% = 1 ELSE gl% = -1
                EXIT DO
            END IF

            ' remove decimals and align.
            j2&& = 0: k2&& = 0
            IF j&& <> 0 OR k&& <> 0 THEN
                IF j&& THEN compa$ = MID$(compa$, 1, INSTR(compa$, ".") - 1) + MID$(compa$, INSTR(compa$, ".") + 1): j2&& = LEN(compa$) - j&& + 1
                IF k&& THEN compb$ = MID$(compb$, 1, INSTR(compb$, ".") - 1) + MID$(compb$, INSTR(compb$, ".") + 1): k2&& = LEN(compb$) - k&& + 1
                compa$ = compa$ + STRING$(k2&& - j2&&, "0")
                compb$ = compb$ + STRING$(j2&& - k2&&, "0")
            END IF
            EXIT WHILE
        WEND

        ' Remove leading zeros if any.
        DO UNTIL LEFT$(compa$, 1) <> "0"
            compa$ = MID$(compa$, 2)
        LOOP
        IF compa$ = "" THEN compa$ = "0"
        DO UNTIL LEFT$(compb$, 1) <> "0"
            compb$ = MID$(compb$, 2)
        LOOP
        IF compb$ = "" THEN compb$ = "0"

        ' Both positive or both negative whole numbers.

        SELECT CASE LEN(compa$)
            CASE IS < LEN(compb$)
                gl% = -1
            CASE IS = LEN(compb$)
                IF compa$ = compb$ THEN
                    gl% = 0
                ELSEIF compa$ > compb$ THEN gl% = 1
                ELSEIF compa$ < compb$ THEN gl% = -1
                END IF
            CASE IS > LEN(compb$)
                gl% = 1
        END SELECT
        EXIT DO
    LOOP
END SUB

SUB sm_add_subtract_router (stringmatha$, operator$, stringmathb$, runningtotal$)
    DIM AS _INTEGER64 a, c, s
    a1$ = stringmatha$: b1$ = stringmathb$
    s = 18: i&& = 0: c = 0

    a$ = stringmatha$: b$ = stringmathb$: op$ = operator$

    IF op$ = "-" THEN
        IF LEFT$(b$, 1) = "-" THEN b$ = MID$(b$, 2) ELSE b$ = "-" + b$
    END IF

    IF INSTR(a$, ".") <> 0 OR INSTR(b$, ".") <> 0 THEN
        decimal% = -1
        IF INSTR(a$, ".") <> 0 THEN
            dec_a&& = LEN(MID$(a$, INSTR(a$, ".") + 1))
            a$ = MID$(a$, 1, INSTR(a$, ".") - 1) + MID$(a$, INSTR(a$, ".") + 1)
        END IF
        IF INSTR(b$, ".") <> 0 THEN
            dec_b&& = LEN(MID$(b$, INSTR(b$, ".") + 1))
            b$ = MID$(b$, 1, INSTR(b$, ".") - 1) + MID$(b$, INSTR(b$, ".") + 1)
        END IF
        ' Line up decimal places by inserting trailing zeros.
        IF dec_b&& > dec_a&& THEN
            j&& = dec_b&&
            a$ = a$ + STRING$(dec_b&& - dec_a&&, "0")
        ELSE
            j&& = dec_a&&
            b$ = b$ + STRING$(dec_a&& - dec_b&&, "0")
        END IF
    END IF

    IF LEFT$(a$, 1) = "-" OR LEFT$(b$, 1) = "-" THEN
        IF LEFT$(a$, 1) = "-" AND LEFT$(b$, 1) = "-" THEN
            sign$ = "": a$ = MID$(a$, 2): b$ = MID$(b$, 2)
        ELSE
            IF LEFT$(a$, 1) = "-" THEN a$ = MID$(a$, 2): sign_a$ = "-"
            IF LEFT$(b$, 1) = "-" THEN b$ = MID$(b$, 2): sign_b$ = "-"

            IF LEFT$(a1$, 1) = "-" THEN a1_x$ = MID$(a1$, 2) ELSE a1_x$ = a1$
            IF LEFT$(b1$, 1) = "-" THEN b1_x$ = MID$(b1$, 2) ELSE b1_x$ = b1$

            sm_greater_lesser a1_x$, b1_x$, gl%

            IF gl% < 0 THEN
                IF LEN(sign_b$) THEN sign$ = "-": SWAP a$, b$
            ELSE
                IF LEN(sign_a$) THEN sign$ = "-": SWAP sign_a$, sign_b$
            END IF
        END IF
    END IF

    z$ = ""
    ' Addition and subtraction of digits.
    DO
        i&& = i&& + s
        x1$ = MID$(a$, LEN(a$) - i&& + 1, s)
        x2$ = MID$(b$, LEN(b$) - i&& + 1, s)
        IF LEN(x2$) > LEN(x1$) THEN SWAP x1$, x2$
        a = VAL(sign_a$ + x1$) + VAL(sign_b$ + x2$) + c
        IF x1$ + x2$ = "" AND c = 0 THEN EXIT DO
        c = 0
        IF a > VAL(STRING$(s, "9")) THEN a = a - 10 ^ s: c = 1
        IF a < 0 THEN a = a + 10 ^ s: c = -1 ' a will never be less than 0.
        tmp$ = LTRIM$(STR$(a))
        z$ = STRING$(LEN(x1$) - LEN(tmp$), "0") + tmp$ + z$
    LOOP

    IF decimal% THEN
        z$ = MID$(z$, 1, LEN(z$) - j&&) + "." + MID$(z$, LEN(z$) - j&& + 1)
    END IF

    ' Remove any leading zeros.
    DO
        IF LEFT$(z$, 1) = "0" THEN z$ = MID$(z$, 2) ELSE EXIT DO
    LOOP

    IF z$ = "" OR z$ = "0" THEN z$ = "0" ELSE z$ = LEFT$(sign$, 1) + z$

    runningtotal$ = z$

    sign$ = "": sign_a$ = "": sign_b$ = "": i&& = 0: j&& = 0: decimal% = 0: c = 0
END SUB

FUNCTION sm_add$ (stringmatha$, stringmathb$)
    operator$ = "+"
    sm_add_subtract_router stringmatha$, operator$, stringmathb$, runningtotal$
    sm_add$ = runningtotal$
END FUNCTION

FUNCTION sm_sub$ (stringmatha$, stringmathb$)
    operator$ = "-"
    sm_add_subtract_router stringmatha$, operator$, stringmathb$, runningtotal$
    sm_sub$ = runningtotal$
END FUNCTION

FUNCTION sm_mult$ (stringmatha$, stringmathb$)
    DIM AS _INTEGER64 a, c, aa, cc, s, ss
    z$ = "": sign$ = "": mult&& = 0: h&& = 0: i&& = 0: j&& = 0: c = 0: decimal% = 0
    zz$ = "": ii&& = 0: jj&& = 0
    s = 8: ss = 18

    a$ = stringmatha$: b$ = stringmathb$

    IF INSTR(a$, "-") <> 0 OR INSTR(b$, "-") <> 0 THEN
        IF INSTR(a$, "-") <> 0 AND INSTR(b$, "-") <> 0 THEN
            a$ = MID$(a$, 2): b$ = MID$(b$, 2)
        ELSE
            IF INSTR(a$, "-") <> 0 THEN a$ = MID$(a$, 2) ELSE b$ = MID$(b$, 2)
            sign$ = "-"
        END IF
    END IF

    IF INSTR(a$, ".") <> 0 OR INSTR(b$, ".") <> 0 THEN
        decimal% = -1
        IF INSTR(a$, ".") <> 0 THEN
            dec_a&& = LEN(MID$(a$, INSTR(a$, ".") + 1))
            a$ = MID$(a$, 1, INSTR(a$, ".") - 1) + MID$(a$, INSTR(a$, ".") + 1)
        END IF
        IF INSTR(b$, ".") <> 0 THEN
            dec_b&& = LEN(MID$(b$, INSTR(b$, ".") + 1))
            b$ = MID$(b$, 1, INSTR(b$, ".") - 1) + MID$(b$, INSTR(b$, ".") + 1)
        END IF
    END IF

    IF LEN(a$) < LEN(b$) THEN SWAP a$, b$ ' Needed so x1$ is always the largest for leading zero replacements.
    ' Multiplication of digits.
    DO
        h&& = h&& + s: i&& = 0
        x2$ = MID$(b$, LEN(b$) - h&& + 1, s)
        DO
            i&& = i&& + s
            x1$ = MID$(a$, LEN(a$) - i&& + 1, s)
            a = VAL(x1$) * VAL(x2$) + c
            c = 0
            tmp$ = LTRIM$(STR$(a))
            IF LEN(tmp$) > s THEN c = VAL(MID$(tmp$, 1, LEN(tmp$) - s)): tmp$ = MID$(tmp$, LEN(tmp$) - s + 1)
            z$ = STRING$(LEN(x1$) - LEN(tmp$), "0") + tmp$ + z$
        LOOP UNTIL i&& >= LEN(a$) AND c = 0

        jj&& = jj&& + 1

        IF jj&& > 1 THEN
            ii&& = 0: cc = 0
            aa$ = holdaa$
            bb$ = z$ + STRING$((jj&& - 1) * s, "0")
            ' Addition only of digits.
            DO
                ii&& = ii&& + ss
                xx1$ = MID$(aa$, LEN(aa$) - ii&& + 1, ss)
                xx2$ = MID$(bb$, LEN(bb$) - ii&& + 1, ss)
                IF LEN(xx1$) < LEN(xx2$) THEN SWAP xx1$, xx2$
                aa = VAL(xx1$) + VAL(xx2$) + cc
                IF xx1$ + xx2$ = "" AND cc = 0 THEN EXIT DO ' Prevents leading zeros.
                cc = 0
                IF aa > VAL(STRING$(ss, "9")) THEN aa = aa - 10 ^ ss: cc = 1
                tmp$ = LTRIM$(STR$(aa))
                zz$ = STRING$(LEN(xx1$) - LEN(tmp$), "0") + tmp$ + zz$
            LOOP

            DO WHILE LEFT$(zz$, 1) = "0"
                IF LEFT$(zz$, 1) = "0" THEN zz$ = MID$(zz$, 2)
            LOOP
            IF zz$ = "" THEN zz$ = "0"

            holdaa$ = zz$
        ELSE
            holdaa$ = z$ + STRING$(jj&& - 1, "0")
        END IF

        z$ = "": zz$ = ""

    LOOP UNTIL h&& >= LEN(b$)

    z$ = holdaa$

    IF decimal% THEN
        DO UNTIL LEN(z$) >= dec_a&& + dec_b&&
            z$ = "0" + z$
        LOOP

        z$ = MID$(z$, 0, LEN(z$) - (dec_a&& + dec_b&& - 1)) + "." + MID$(z$, LEN(z$) - (dec_a&& + dec_b&&) + 1)

        DO UNTIL RIGHT$(z$, 1) <> "0" AND RIGHT$(z$, 1) <> "."
            z$ = MID$(z$, 1, LEN(z$) - 1)
        LOOP
    END IF

    IF STRING$(LEN(z$), "0") = z$ OR z$ = "" OR z$ = "0" THEN z$ = "0" ELSE z$ = sign$ + z$

    decimal% = 0: sign$ = ""

    runningtotal$ = z$
    sm_mult$ = z$
END FUNCTION

FUNCTION sm_div$ (stringmatha$, stringmathb$)
    hold_stringmatha$ = stringmatha$: hold_stringmathb$ = stringmathb$
    q$ = "": divisor$ = stringmathb$: dividend$ = stringmatha$
    DO ' Falx loop.
        'Strip off neg(s) and determine quotent sign.
        IF LEFT$(divisor$, 1) = "-" THEN divisor$ = MID$(divisor$, 2): q$ = "-"
        IF LEFT$(dividend$, 1) = "-" THEN dividend$ = MID$(dividend$, 2): IF q$ = "-" THEN q$ = "" ELSE q$ = "-"

        ' Quick results for divisor 1 or 0.
        IF dividend$ = "0" THEN q$ = "0": EXIT DO
        IF divisor$ = "1" THEN q$ = dividend$: EXIT DO
        IF divisor$ = "0" THEN q$ = "Division by zero not possible.": EXIT DO

        ' Determine decimal direction. -1 to left, +1 to right.
        gl% = 0: sm_greater_lesser divisor$, dividend$, gl%
        IF betatest% AND gl% = 1 THEN PRINT divisor$; " > "; dividend$; " Move decimal to the left"
        IF betatest% AND gl% = 0 THEN PRINT divisor$; " = "; dividend$
        IF betatest% AND gl% = -1 THEN PRINT divisor$; " < "; dividend$; " Move deciml to the right."
        IF gl% = 1 THEN ' Divisor is larger than dividend so decimal moves to the left.
            div_decimal% = -1 ' Move decimal point to the left.
        ELSEIF gl% = -1 THEN
            div_decimal% = 1 ' Move decimal point to the right.
        ELSE
            ' Divisor and dividend are the same number.
            q$ = q$ + "1": EXIT DO
        END IF
        divisor_ratio_dividend% = gl%

        ' Strip off decimal point(s) and determine places in these next 2 routines.
        dp&& = 0: dp2&& = 0: j2&& = 0
        temp&& = INSTR(divisor$, ".")
        IF temp&& THEN
            divisor$ = MID$(divisor$, 1, temp&& - 1) + MID$(divisor$, temp&& + 1)
            IF temp&& = 1 THEN
                DO UNTIL LEFT$(divisor$, 1) <> "0" ' Strip off any leading zeros on divisor only.
                    divisor$ = MID$(divisor$, 2)
                    dp&& = dp&& + 1
                LOOP
                dp&& = dp&& + 1
            ELSE
                dp&& = -(temp&& - 2)
            END IF
        ELSE
            dp&& = -(LEN(divisor$) - 1)
        END IF
        temp&& = INSTR(dividend$, ".")
        IF temp&& THEN
            dividend$ = MID$(dividend$, 1, temp&& - 1) + MID$(dividend$, temp&& + 1)
            IF temp&& = 1 THEN
                DO UNTIL LEFT$(dividend$, 1) <> "0" ' Strip off any leading zeros on divisor only.
                    dividend$ = MID$(dividend$, 2)
                    dp2&& = dp2&& + 1
                LOOP
                dp2&& = dp2&& + 1
            ELSE
                dp2&& = -(temp&& - 2)
            END IF
        ELSE
            dp2&& = -(LEN(dividend$) - 1)
        END IF
        IF betatest% THEN COLOR 11: PRINT "Divisor decimal moves "; LTRIM$(STR$(dp&&)); ". Dividend decimal moves"; LTRIM$(STR$(dp2&&)); ". Quotent decimal ABS("; LTRIM$(STR$(dp&&)); " - "; LTRIM$(STR$(dp2&&)); ") =";: COLOR 14: PRINT ABS(dp&& - dp2&&);: COLOR 11: PRINT "+ any adjustment.": COLOR 7
        dp&& = ABS(dp&& - dp2&&)

        IF betatest% THEN PRINT "Divisor 1st# = "; MID$(divisor$, 1, 1); "  Remainder 1st# = "; MID$(dividend$, 1, 1)

        ' Adjust decimal place for instances when divisor is larger than remainder the length of the divisor.
        j% = 0
        IF MID$(divisor$, 1, 1) > MID$(dividend$, 1, 1) THEN
            j% = 1
            IF betatest% THEN PRINT "Larger divisor, so move quotent decimal one place back to: ";: COLOR 14: PRINT LTRIM$(STR$(dp&&)): COLOR 7
        ELSEIF MID$(divisor$, 1, 1) = MID$(dividend$, 1, 1) THEN
            IF LEN(divisor$) = LEN(dividend$) THEN
                IF divisor$ > dividend$ THEN j% = 1
            ELSE
                IF LEN(divisor$) > LEN(dividend$) THEN
                    temp$ = dividend$ + STRING$(LEN(divisor$) - LEN(dividend$), "0")
                ELSE
                    temp$ = MID$(dividend$, 1, LEN(divisor$))
                END IF
                IF divisor$ > temp$ THEN j% = 1
            END IF
            IF j% THEN
                dp&& = dp&& - div_decimal%
                IF betatest% THEN PRINT "Larger divisor than dividend at LEN(divisor$), so move quotent decimal one place back to: ";: COLOR 14: PRINT LTRIM$(STR$(dp&&)): COLOR 7
            ELSE
                IF betatest% THEN PRINT "Smaller divisor than dividend at LEN(divisor$), so no quotent decimal place adjustment needed. Quotent decimal place = ";: COLOR 14: PRINT LTRIM$(STR$(dp&&)): COLOR 7
            END IF
        ELSE
            j% = 0
            IF betatest% THEN PRINT "Smaller divisor, so no quotent decimal place adjustment needed. Quotent decimal place = ";: COLOR 14: PRINT LTRIM$(STR$(dp&&)): COLOR 7
        END IF
        IF j% THEN dp&& = dp&& - div_decimal%

        origdividend$ = dividend$
        ' Determine length of divisor and dividend to begin initial long divison step.
        gl% = 2: sm_greater_lesser divisor$, MID$(dividend$, 1, LEN(divisor$)) + STRING$(LEN(divisor$) - LEN(dividend$), "0"), gl%
        divisor_ratio_dividend% = gl%
        IF gl% = 1 AND MID$(dividend$, 1, 1) <> "0" THEN
            dividend$ = MID$(dividend$, 1, LEN(divisor$) + 1) + STRING$(LEN(divisor$) + 1 - LEN(dividend$), "0")
        ELSE
            dividend$ = MID$(dividend$, 1, LEN(divisor$)) + STRING$(LEN(divisor$) - LEN(dividend$), "0")
        END IF

        ' Long divison loop. Mult and subtraction of dividend and remainder.
        k&& = 0
        IF betatest% THEN PRINT "Begin long divison loop..."
        DO
            SELECT CASE MID$(divisor$, 1, 1)
                CASE IS < MID$(dividend$, 1, 1)
                    adj_rem_len% = 0
                CASE IS = MID$(dividend$, 1, 1)
                    gl% = 2: sm_greater_lesser divisor$, MID$(dividend$, 1, LEN(divisor$)), gl%
                    IF gl% = 1 THEN adj_rem_len% = 1 ELSE adj_rem_len% = 0
                CASE IS > MID$(dividend$, 1, 1)
                    adj_rem_len% = 1
            END SELECT
            IF j2&& = 0 THEN j2&& = LEN(divisor$) + adj_rem_len%
            DO
                IF LEN(divisor$) > LEN(dividend$) THEN
                    w3&& = 0: runningtotal$ = dividend$: stringmathb$ = "0"
                    IF betatest% THEN PRINT: COLOR 3: PRINT "Divisor is larger so "; dividend$; " \ "; divisor$; " =";: COLOR 5: PRINT w3&&: COLOR 7
                    EXIT DO
                END IF
                IF LEN(divisor$) = LEN(dividend$) THEN
                    gl% = 2: sm_greater_lesser divisor$, dividend$, gl%
                    IF gl% = 1 THEN
                        w3&& = 0: runningtotal$ = dividend$: stringmathb$ = "0"
                        IF betatest% THEN COLOR 9: PRINT "Length of divisor is the same as remainder but remainder is smaller so w3&& = ";: COLOR 5: PRINT "0": COLOR 7
                        EXIT DO
                    END IF
                END IF
                SELECT CASE LEN(dividend$)
                    CASE IS > 2
                        w3&& = VAL(MID$(dividend$, 1, 2 + adj_rem_len%)) \ VAL(MID$(divisor$, 1, 2))
                        IF betatest% THEN PRINT MID$(dividend$, 1, 2 + adj_rem_len%); " \ "; MID$(divisor$, 1, 2); " =";
                    CASE ELSE
                        w3&& = VAL(MID$(dividend$, 1, 1 + adj_rem_len%)) \ VAL(MID$(divisor$, 1, 1))
                        IF betatest% THEN PRINT MID$(dividend$, 1, 1 + adj_rem_len%); " \ "; MID$(divisor$, 1, 1); " =";
                END SELECT
                IF betatest% THEN COLOR 5: PRINT " " + LTRIM$(STR$(w3&&));: COLOR 7: PRINT ". Begin mult est. at or one above this number."
                IF w3&& < 9 THEN w3&& = w3&& + 1 ELSE IF w3&& = 10 THEN w3&& = 9
                DO
                    stringmatha$ = divisor$: stringmathb$ = LTRIM$(STR$(w3&&))
                    runningtotal$ = sm_mult$(divisor$, LTRIM$(STR$(w3&&)))
                    gl% = 2: sm_greater_lesser runningtotal$, dividend$, gl%
                    IF gl% <= 0 OR w3&& = 0 THEN EXIT DO
                    IF betatest% THEN COLOR 8: PRINT "Mult loop:"; w3&&; "* "; divisor$; " = "; runningtotal$: COLOR 7
                    w3&& = w3&& - 1
                LOOP
                stringmatha$ = dividend$: stringmathb$ = runningtotal$
                sm_add_subtract_router dividend$, "-", stringmathb$, runningtotal$
                EXIT DO
            LOOP
            IF betatest% THEN PRINT LTRIM$(STR$(w3&&)); " * "; divisor$; " = "; stringmathb$; " | "; stringmatha$; " - "; stringmathb$; " = "; runningtotal$; " Remainder and drop-down = ";
            j2&& = j2&& + 1
            drop$ = "0": MID$(drop$, 1, 1) = MID$(origdividend$, j2&&, 1)
            IF runningtotal$ <> "0" THEN remainder$ = runningtotal$ ELSE remainder$ = ""
            dividend$ = remainder$ + drop$
            w3$ = LTRIM$(STR$(w3&&))
            temp$ = ""
            IF div_decimal% = -1 THEN
                IF dp&& AND k&& = 0 THEN
                    q$ = q$ + "." + STRING$(dp&& - 1, "0")
                    IF w3&& = 0 THEN w3$ = ""
                END IF
            END IF
            IF div_decimal% >= 0 THEN
                IF dp&& = k&& THEN
                    temp$ = "."
                END IF
            END IF
            q$ = q$ + w3$ + temp$
            IF betatest% AND remainder$ = "" THEN betatemp$ = CHR$(34) + CHR$(34) ELSE IF betatest% THEN betatemp$ = remainder$
            IF betatest% AND MID$(origdividend$, j2&&, 1) = "" THEN betatemp2$ = CHR$(34) + CHR$(34) ELSE IF betatest% THEN betatemp2$ = MID$(origdividend$, j2&&, 1)
            IF betatest% THEN PRINT dividend$; " ("; betatemp$; " +  "; drop$; ") at:"; j2&&; "of "; origdividend$; "  Loop"; k&& + 1; "Quotent = ";: COLOR 14, 4: PRINT q$;: COLOR 7, 0: PRINT: SLEEP
            ' Check to terminate
            IF div_decimal% = -1 THEN
                ' Decimal to left.
                IF remainder$ = "" AND MID$(origdividend$, j2&&, 1) = "" OR LEN(q$) >= limit&& THEN EXIT DO
            ELSE
                ' Decimal to right.
                IF remainder$ = "" AND MID$(origdividend$, j2&&, 1) = "" AND k&& >= dp&& OR LEN(q$) >= limit&& THEN EXIT DO
            END IF

            IF INKEY$ = " " THEN EXIT DO
            k&& = k&& + 1
        LOOP
        EXIT DO
    LOOP
    IF RIGHT$(q$, 1) = "." AND divisor$ <> "0" THEN runningtotal$ = MID$(q$, 1, LEN(q$) - 1) ELSE runningtotal$ = q$
    sm_div$ = runningtotal$
    stringmatha$ = hold_stringmatha$: stringmathb$ = hold_stringmathb$
END FUNCTION

FUNCTION sm_sqrt$ (sm_var$)
    oldy$ = "": sqrt$ = "": custom_limit&& = limit&&: REM IF limit&& < 150 THEN custom_limit&& = 150 ELSE custom_limit&& = limit&&
    sqrt_a$ = sm_var$
    IF INSTR(sqrt_a$, ".") THEN
        decx$ = MID$(sqrt_a$, 1, INSTR(sqrt_a$, ".") - 1)
        sqrt_a$ = MID$(sqrt_a$, 1, INSTR(sqrt_a$, ".") - 1) + MID$(sqrt_a$, INSTR(sqrt_a$, ".") + 1)
        IF LEN(sqrt_a$) = 1 THEN sqrt_a$ = sqrt_a$ + "0"
    ELSE
        decx$ = sqrt_a$
    END IF

    j&& = LEN(decx$)

    ' VAL() okay, one character eval.
    IF VAL(RIGHT$(LTRIM$(STR$(j&&)), 1)) / 2 = VAL(RIGHT$(LTRIM$(STR$(j&&)), 1)) \ 2 THEN
        i&& = 1 ' Even number length.
    ELSE
        i&& = 0 ' Odd number length.
    END IF

    DO
        runningtotal$ = sm_sub$(z$, k$)
        z$ = runningtotal$ + (MID$(sqrt_a$, i&&, 2))
        IF LEFT$(z$, 1) = "0" THEN z$ = MID$(z$, 2) ' Remove leading zeros

        oldy$ = ""
        FOR j&& = 1 TO 10
            IF i&& > 1 THEN
                y$ = sm_mult$(sqrt$, "2")
                y$ = y$ + LTRIM$(STR$(j&&))
            ELSE
                y$ = LTRIM$(STR$(j&&))
            END IF

            runningtotal$ = sm_mult$(y$, LTRIM$(STR$(j&&)))

            sm_greater_lesser runningtotal$, z$, gl%
            IF gl% > -1 THEN
                IF gl% = 0 THEN
                    h% = 0: oldy$ = y$ ' Perfect square division.
                ELSE
                    h% = 1
                END IF
                runningtotal$ = sm_mult$(oldy$, LTRIM$(STR$(j&& - h%)))

                IF STRING$(LEN(z$), "0") = z$ AND runningtotal$ = "0" AND i&& >= LEN(decx$) THEN EXIT DO

                IF dpx&& = 0 THEN ' Limited to && size unless converted to string.
                    IF i&& >= LEN(decx$) THEN
                        dpx&& = INT(LEN(decx$) / 2 + .5)
                        IF dpx&& = 0 THEN dpx&& = -1
                    END IF
                END IF

                IF betatest% < -1 THEN PRINT "Sqrt "; sqrt$; " * 2 = ";: COLOR 2, 0: PRINT LTRIM$(STR$(VAL(sqrt$) * 2));: COLOR 7, 0: PRINT LTRIM$(STR$(j&& - h%)); " * "; LTRIM$(STR$(j&& - h%)); " ="; VAL(oldy$) * (j&& - h%)
                sqrt$ = sqrt$ + LTRIM$(STR$(j&& - h%))

                runningtotal$ = sm_mult$(oldy$, LTRIM$(STR$(j&& - h%)))
                k$ = runningtotal$

                IF betatest% < -1 THEN PRINT "Remainder "; z$; " minus "; k$; " = ";
                EXIT FOR
            END IF
            oldy$ = y$
        NEXT

        i&& = i&& + 2
        IF LEN(z$) >= custom_limit&& THEN EXIT DO
        sqrt_a$ = sqrt_a$ + "00"
    LOOP

    IF dpx&& THEN sqrt$ = MID$(sqrt$, 0, dpx&& + 1) + "." + MID$(sqrt$, dpx&& + 1)
    sm_sqrt$ = sqrt$
END FUNCTION

FUNCTION sm_pow$ (num$, power$)
    IF INSTR(power$, ".") THEN
        t$ = MID$(power$, INSTR(power$, "."))
        power$ = MID$(power$, 1, INSTR(power$, ".") - 1)

        a$ = "1"
        b$ = num$
        x$ = "0"
        y$ = "1"

        highc$ = b$
        lowc$ = a$
        highz$ = "1"

        DO
            t1$ = sm_mult$(a$, b$)
            c$ = sm_sqrt$(t1$)
            t1$ = sm_add(x$, y$)
            z$ = sm_div(t1$, "2")
            sm_greater_lesser z$, t$, gl%
            IF gl% >= 0 THEN
                highz$ = z$: highc$ = c$
            ELSEIF gl% = -1 THEN
                lowz$ = z$: lowc$ = c$
            END IF
            REM PRINT a$, b$, highc$, lowc$, z$, highz$, lowz$
            a$ = highc$: b$ = lowc$
            x$ = highz$: y$ = lowz$
        LOOP UNTIL gl% = 0
        IF LEN(power$) THEN
            'a = num ^ VAL(power$) * a
            temp$ = num$
            FOR i&& = 1 TO VAL(power$) - 1
                temp2$ = sm_mult$(temp$, num$): temp$ = temp2$
            NEXT
            a$ = sm_mult$(temp2$, a$)
        END IF
    ELSE
        'num ^ VAL(power$)
        temp$ = num$
        FOR i&& = 1 TO VAL(power$) - 1
            a$ = sm_mult$(temp$, num$): temp$ = a$
        NEXT
    END IF
    sm_pow$ = a$
END FUNCTION

Pete
Reply
#27
So back to the drawing board. Approximations would require too many rounding rules. Long division works perfectly for square roots, but I still can't get a handle on the extra hoops to apply for nth roots like cube root of 126.

Anyway, here is an optimized update of my previous square root long division method, set to 12 decimal places. It explains the process as it calculates the square root of 8.

Code: (Select All)
$CONSOLE:ONLY
DIM SHARED betatest%: betatest% = -2
num$ = "8"
PRINT sm_sqrt$(num$)
DO: _LIMIT 1: LOOP

FUNCTION sm_sqrt$ (sm_var$)
    sqrt_a$ = sm_var$ ' Convert to prevent sm_var$ from being changed.
    oldy$ = "": sqrt$ = "": k$ = "": z$ = ""
    IF limit&& < 150 THEN custom_limit&& = 12 ELSE custom_limit&& = limit&&
    IF INSTR(sqrt_a$, ".") THEN ' Number is a decimal.
        decx$ = MID$(sqrt_a$, 1, INSTR(sqrt_a$, ".") - 1) ' Whole number portion of number.
        sqrt_a$ = MID$(sqrt_a$, 1, INSTR(sqrt_a$, ".") - 1) + MID$(sqrt_a$, INSTR(sqrt_a$, ".") + 1) ' Remove decimal point, which converts deciaml to whole number number.
        IF LEN(sqrt_a$) = 1 THEN sqrt_a$ = sqrt_a$ + "0"
    ELSE
        decx$ = sqrt_a$ ' Whole number.
    END IF

    h&& = LEN(decx$) ' The number of digits of the whole number (portion).

    IF h&& / 2 = h&& \ 2 THEN i&& = 1 ELSE i&& = 0 ' 0 = Odd vs 1 = even number of digits in whole number (portion).

    ' Varible review:
    ' sqrt_a$ is the entire number with any decimal point removed.
    ' decx$ is the whole number (portion) of the number.
    ' h&& is number of digits in the whole number (portion).
    ' i&& index for parsing sqrt_a$ for drop-down division. If hh& is odd index starts at zero. Index at 1 if h&& is even.
    ' sqrt$ is the root answer per each iteration.
    ' custom_limit&& is the max. number of digits to evaluate the root number.

    DO
        IF betatest% < -1 THEN PRINT "Combine remainder ";: COLOR 12: PRINT sm_sub$(z$, k$);: COLOR 7: PRINT " with ";
        z$ = sm_sub$(z$, k$) + (MID$(sqrt_a$, i&&, 2))
        IF LEFT$(z$, 1) = "0" THEN z$ = MID$(z$, 2) ' Remove any leading zero.
        IF betatest% < -1 THEN PRINT MID$(sqrt_a$, 1, i&& - 1);: COLOR 9: PRINT MID$(sqrt_a$, i&&, 2);: COLOR 7: PRINT MID$(sqrt_a$, i&& + 2); " and remove any leading zero to = ";: COLOR 6: PRINT z$;: COLOR 7: PRINT " as the target."
        FOR j&& = 1 TO 10
            IF i&& > 1 THEN
                y$ = sm_mult$(sqrt$, "2") + LTRIM$(STR$(j&&))
                COLOR 2: PRINT "y$ = (sqrt$ * 2 ~ j&& * J&&): "; sqrt$; " * 2 = "; sm_mult$(sqrt$, "2"); " ~"; j&&; "= "; y$; " *"; j&&; "= "; sm_mult$(y$, LTRIM$(STR$(j&&))): COLOR 7
            ELSE
                y$ = LTRIM$(STR$(j&&)) ' 1st loop starts here as there is no sqrt$ yet.
                COLOR 2: PRINT "y$: j&& ="; j&&; "y$ is same as j&& = "; y$; " *"; j&&; " = "; sm_mult$(y$, LTRIM$(STR$(j&&))): COLOR 7
            END IF

            sm_greater_lesser sm_mult$(y$, LTRIM$(STR$(j&&))), z$, gl%
            IF gl% > -1 THEN ' 0 = perfect square division. 1 = Too big so use the previous iteration.
                IF gl% = 0 THEN
                    IF betatest% < -1 THEN PRINT "gl% ="; gl%; " Perfect square division. j&& =";: COLOR 14: PRINT j&&: COLOR 7
                    oldy$ = y$ ' Perfect square division. Not over, so do not subtract 1. j&& =";: COLOR 14: PRINT j&& - 1: COLOR 7
                ELSE
                    IF betatest% < -1 THEN PRINT "gl% ="; gl%; " Estimate over target: "; sm_mult$(y$, LTRIM$(STR$(j&&))); " > "; z$; " so j&& =";: COLOR 14: PRINT j&& - 1: COLOR 7
                    j&& = j&& - 1 ' Adjusts size to the previous iteration.
                END IF

                IF STRING$(LEN(z$), "0") = z$ AND i&& >= h&& THEN
                    IF betatest% < -1 THEN PRINT "Checking for exit as z$ is null and i&&"; i&&; ">= h&&"; h&&; " so if oldy$ "; oldy$; " = zero then exit."
                    IF sm_mult$(oldy$, LTRIM$(STR$(j&&))) = "0" THEN EXIT DO
                END IF

                IF dpx&& = 0 THEN ' Decimal point relocator. Limited to && size unless converted to string.
                    IF i&& >= h&& THEN
                        dpx&& = INT(h&& / 2 + .5)
                        IF dpx&& = 0 THEN dpx&& = -1 ' Do not set to zero as -1 accomplishes the same thing and prevents ongoing loops here.
                    END IF
                END IF

                IF betatest% < -1 THEN PRINT "Sqrt combined with j&& * j&&: ";: temp$ = LTRIM$(STR$(VAL(MID$(sqrt$, 1, 1)))) + MID$(sqrt$, 2): PRINT temp$; " * 2 = "; LTRIM$(STR$(VAL(sqrt$) * 2));: COLOR 14: PRINT LTRIM$(STR$(j&&));: COLOR 7: PRINT " * ";: COLOR 14: PRINT LTRIM$(STR$(j&&));: COLOR 7: PRINT " =";: COLOR 5: PRINT VAL(oldy$) * j&&;: COLOR 7: PRINT " This is k$."
                sqrt$ = sqrt$ + LTRIM$(STR$(j&&))

                k$ = sm_mult$(oldy$, LTRIM$(STR$(j&&)))

                IF betatest% < -1 THEN PRINT "Remainder ";: COLOR 6: PRINT z$;: COLOR 7: PRINT " - ";: COLOR 5: PRINT k$;: COLOR 7: PRINT " = ";: COLOR 12: PRINT sm_sub$(z$, k$): COLOR 7
                EXIT FOR
            END IF
            oldy$ = y$
        NEXT
        oldy$ = ""
        IF betatest% < -1 THEN PRINT "Increase index by 2 so i&& ="; i&& + 2
        i&& = i&& + 2
        IF betatest% <= -1 THEN IF LEN(z$) >= custom_limit&& THEN PRINT "Max. digits reached. Exiting..."
        IF LEN(z$) >= custom_limit&& THEN EXIT DO
        sqrt_a$ = sqrt_a$ + "00"
        IF betatest% < -1 THEN PRINT "Multiply sqrt_a$ "; MID$(sqrt_a$, 1, LEN(sqrt_a$) - 2); " * 100 = "; sqrt_a$: SLEEP
    LOOP

    IF dpx&& THEN
        sm_sqrt$ = MID$(sqrt$, 0, dpx&& + 1) + "." + MID$(sqrt$, dpx&& + 1)
    ELSE
        sm_sqrt$ = sqrt$
    END IF

END FUNCTION

''----------------------------------------

SUB sm_greater_lesser (stringmatha$, stringmathb$, gl%)
    compa$ = stringmatha$: compb$ = stringmathb$ ' So original variables do not get changed.
    DO
        WHILE -1 ' Falx loop.
            IF gl% = 2 THEN EXIT WHILE ' For bypassing sign and decimal adjustments when only positive non-decimal numbers are being evaluated.
            ' Remove trailing zeros after a decimal point.
            IF INSTR(compa$, ".") THEN
                DO UNTIL RIGHT$(compa$, 1) <> "0" AND RIGHT$(compa$, 1) <> "." AND RIGHT$(compa$, 1) <> "-"
                    compa$ = MID$(compa$, 1, LEN(compa$) - 1)
                LOOP
            END IF
            IF INSTR(compb$, ".") THEN
                DO UNTIL RIGHT$(compb$, 1) <> "0" AND RIGHT$(compb$, 1) <> "." AND RIGHT$(compb$, 1) <> "-"
                    compb$ = MID$(compb$, 1, LEN(compb$) - 1)
                LOOP
            END IF

            IF MID$(compa$, 1, 2) = "-0" OR compa$ = "" OR compa$ = "-" THEN compa$ = "0"
            IF MID$(compb$, 1, 2) = "-0" OR compb$ = "" OR compb$ = "-" THEN compb$ = "0"

            ' A - and +
            j% = 0: k% = 0
            IF LEFT$(compa$, 1) = "-" THEN j% = -1
            IF LEFT$(compb$, 1) = "-" THEN k% = -1
            IF k% = 0 AND j% THEN gl% = -1: EXIT DO
            IF j% = 0 AND k% THEN gl% = 1: EXIT DO

            j&& = INSTR(compa$, ".")
            k&& = INSTR(compb$, ".")

            ' A starting decimal and non-decimal.
            IF j&& = 0 AND k&& = 1 THEN
                IF compa$ = "0" THEN gl% = -1 ELSE gl% = 1
                EXIT DO
            END IF
            IF k&& = 0 AND j&& = 1 THEN
                IF compb$ = "0" THEN gl% = 1 ELSE gl% = -1
                EXIT DO
            END IF

            ' remove decimals and align.
            j2&& = 0: k2&& = 0
            IF j&& <> 0 OR k&& <> 0 THEN
                IF j&& THEN compa$ = MID$(compa$, 1, INSTR(compa$, ".") - 1) + MID$(compa$, INSTR(compa$, ".") + 1): j2&& = LEN(compa$) - j&& + 1
                IF k&& THEN compb$ = MID$(compb$, 1, INSTR(compb$, ".") - 1) + MID$(compb$, INSTR(compb$, ".") + 1): k2&& = LEN(compb$) - k&& + 1
                compa$ = compa$ + STRING$(k2&& - j2&&, "0")
                compb$ = compb$ + STRING$(j2&& - k2&&, "0")
            END IF
            EXIT WHILE
        WEND

        ' Remove leading zeros if any.
        DO UNTIL LEFT$(compa$, 1) <> "0"
            compa$ = MID$(compa$, 2)
        LOOP
        IF compa$ = "" THEN compa$ = "0"
        DO UNTIL LEFT$(compb$, 1) <> "0"
            compb$ = MID$(compb$, 2)
        LOOP
        IF compb$ = "" THEN compb$ = "0"

        ' Both positive or both negative whole numbers.

        SELECT CASE LEN(compa$)
            CASE IS < LEN(compb$)
                gl% = -1
            CASE IS = LEN(compb$)
                IF compa$ = compb$ THEN
                    gl% = 0
                ELSEIF compa$ > compb$ THEN gl% = 1
                ELSEIF compa$ < compb$ THEN gl% = -1
                END IF
            CASE IS > LEN(compb$)
                gl% = 1
        END SELECT
        EXIT DO
    LOOP
END SUB

SUB sm_add_subtract_router (stringmatha$, operator$, stringmathb$, runningtotal$)
    DIM AS _INTEGER64 a, c, s
    a1$ = stringmatha$: b1$ = stringmathb$
    s = 18: i&& = 0: c = 0

    a$ = stringmatha$: b$ = stringmathb$: op$ = operator$

    IF op$ = "-" THEN
        IF LEFT$(b$, 1) = "-" THEN b$ = MID$(b$, 2) ELSE b$ = "-" + b$
    END IF

    IF INSTR(a$, ".") <> 0 OR INSTR(b$, ".") <> 0 THEN
        decimal% = -1
        IF INSTR(a$, ".") <> 0 THEN
            dec_a&& = LEN(MID$(a$, INSTR(a$, ".") + 1))
            a$ = MID$(a$, 1, INSTR(a$, ".") - 1) + MID$(a$, INSTR(a$, ".") + 1)
        END IF
        IF INSTR(b$, ".") <> 0 THEN
            dec_b&& = LEN(MID$(b$, INSTR(b$, ".") + 1))
            b$ = MID$(b$, 1, INSTR(b$, ".") - 1) + MID$(b$, INSTR(b$, ".") + 1)
        END IF
        ' Line up decimal places by inserting trailing zeros.
        IF dec_b&& > dec_a&& THEN
            j&& = dec_b&&
            a$ = a$ + STRING$(dec_b&& - dec_a&&, "0")
        ELSE
            j&& = dec_a&&
            b$ = b$ + STRING$(dec_a&& - dec_b&&, "0")
        END IF
    END IF

    IF LEFT$(a$, 1) = "-" OR LEFT$(b$, 1) = "-" THEN
        IF LEFT$(a$, 1) = "-" AND LEFT$(b$, 1) = "-" THEN
            sign$ = "": a$ = MID$(a$, 2): b$ = MID$(b$, 2)
        ELSE
            IF LEFT$(a$, 1) = "-" THEN a$ = MID$(a$, 2): sign_a$ = "-"
            IF LEFT$(b$, 1) = "-" THEN b$ = MID$(b$, 2): sign_b$ = "-"

            IF LEFT$(a1$, 1) = "-" THEN a1_x$ = MID$(a1$, 2) ELSE a1_x$ = a1$
            IF LEFT$(b1$, 1) = "-" THEN b1_x$ = MID$(b1$, 2) ELSE b1_x$ = b1$

            sm_greater_lesser a1_x$, b1_x$, gl%

            IF gl% < 0 THEN
                IF LEN(sign_b$) THEN sign$ = "-": SWAP a$, b$
            ELSE
                IF LEN(sign_a$) THEN sign$ = "-": SWAP sign_a$, sign_b$
            END IF
        END IF
    END IF

    z$ = ""
    ' Addition and subtraction of digits.
    DO
        i&& = i&& + s
        x1$ = MID$(a$, LEN(a$) - i&& + 1, s)
        x2$ = MID$(b$, LEN(b$) - i&& + 1, s)
        IF LEN(x2$) > LEN(x1$) THEN SWAP x1$, x2$
        a = VAL(sign_a$ + x1$) + VAL(sign_b$ + x2$) + c
        IF x1$ + x2$ = "" AND c = 0 THEN EXIT DO
        c = 0
        IF a > VAL(STRING$(s, "9")) THEN a = a - 10 ^ s: c = 1
        IF a < 0 THEN a = a + 10 ^ s: c = -1 ' a will never be less than 0.
        tmp$ = LTRIM$(STR$(a))
        z$ = STRING$(LEN(x1$) - LEN(tmp$), "0") + tmp$ + z$
    LOOP

    IF decimal% THEN
        z$ = MID$(z$, 1, LEN(z$) - j&&) + "." + MID$(z$, LEN(z$) - j&& + 1)
    END IF

    ' Remove any leading zeros.
    DO
        IF LEFT$(z$, 1) = "0" THEN z$ = MID$(z$, 2) ELSE EXIT DO
    LOOP

    IF z$ = "" OR z$ = "0" THEN z$ = "0" ELSE z$ = LEFT$(sign$, 1) + z$

    runningtotal$ = z$

    sign$ = "": sign_a$ = "": sign_b$ = "": i&& = 0: j&& = 0: decimal% = 0: c = 0
END SUB

FUNCTION sm_add$ (stringmatha$, stringmathb$)
    operator$ = "+"
    sm_add_subtract_router stringmatha$, operator$, stringmathb$, runningtotal$
    sm_add$ = runningtotal$
END FUNCTION

FUNCTION sm_sub$ (stringmatha$, stringmathb$)
    operator$ = "-"
    sm_add_subtract_router stringmatha$, operator$, stringmathb$, runningtotal$
    sm_sub$ = runningtotal$
END FUNCTION

FUNCTION sm_mult$ (stringmatha$, stringmathb$)
    DIM AS _INTEGER64 a, c, aa, cc, s, ss
    z$ = "": sign$ = "": mult&& = 0: h&& = 0: i&& = 0: j&& = 0: c = 0: decimal% = 0
    zz$ = "": ii&& = 0: jj&& = 0
    s = 8: ss = 18

    a$ = stringmatha$: b$ = stringmathb$

    IF INSTR(a$, "-") <> 0 OR INSTR(b$, "-") <> 0 THEN
        IF INSTR(a$, "-") <> 0 AND INSTR(b$, "-") <> 0 THEN
            a$ = MID$(a$, 2): b$ = MID$(b$, 2)
        ELSE
            IF INSTR(a$, "-") <> 0 THEN a$ = MID$(a$, 2) ELSE b$ = MID$(b$, 2)
            sign$ = "-"
        END IF
    END IF

    IF INSTR(a$, ".") <> 0 OR INSTR(b$, ".") <> 0 THEN
        decimal% = -1
        IF INSTR(a$, ".") <> 0 THEN
            dec_a&& = LEN(MID$(a$, INSTR(a$, ".") + 1))
            a$ = MID$(a$, 1, INSTR(a$, ".") - 1) + MID$(a$, INSTR(a$, ".") + 1)
        END IF
        IF INSTR(b$, ".") <> 0 THEN
            dec_b&& = LEN(MID$(b$, INSTR(b$, ".") + 1))
            b$ = MID$(b$, 1, INSTR(b$, ".") - 1) + MID$(b$, INSTR(b$, ".") + 1)
        END IF
    END IF

    IF LEN(a$) < LEN(b$) THEN SWAP a$, b$ ' Needed so x1$ is always the largest for leading zero replacements.
    ' Multiplication of digits.
    DO
        h&& = h&& + s: i&& = 0
        x2$ = MID$(b$, LEN(b$) - h&& + 1, s)
        DO
            i&& = i&& + s
            x1$ = MID$(a$, LEN(a$) - i&& + 1, s)
            a = VAL(x1$) * VAL(x2$) + c
            c = 0
            tmp$ = LTRIM$(STR$(a))
            IF LEN(tmp$) > s THEN c = VAL(MID$(tmp$, 1, LEN(tmp$) - s)): tmp$ = MID$(tmp$, LEN(tmp$) - s + 1)
            z$ = STRING$(LEN(x1$) - LEN(tmp$), "0") + tmp$ + z$
        LOOP UNTIL i&& >= LEN(a$) AND c = 0

        jj&& = jj&& + 1

        IF jj&& > 1 THEN
            ii&& = 0: cc = 0
            aa$ = holdaa$
            bb$ = z$ + STRING$((jj&& - 1) * s, "0")
            ' Addition only of digits.
            DO
                ii&& = ii&& + ss
                xx1$ = MID$(aa$, LEN(aa$) - ii&& + 1, ss)
                xx2$ = MID$(bb$, LEN(bb$) - ii&& + 1, ss)
                IF LEN(xx1$) < LEN(xx2$) THEN SWAP xx1$, xx2$
                aa = VAL(xx1$) + VAL(xx2$) + cc
                IF xx1$ + xx2$ = "" AND cc = 0 THEN EXIT DO ' Prevents leading zeros.
                cc = 0
                IF aa > VAL(STRING$(ss, "9")) THEN aa = aa - 10 ^ ss: cc = 1
                tmp$ = LTRIM$(STR$(aa))
                zz$ = STRING$(LEN(xx1$) - LEN(tmp$), "0") + tmp$ + zz$
            LOOP

            DO WHILE LEFT$(zz$, 1) = "0"
                IF LEFT$(zz$, 1) = "0" THEN zz$ = MID$(zz$, 2)
            LOOP
            IF zz$ = "" THEN zz$ = "0"

            holdaa$ = zz$
        ELSE
            holdaa$ = z$ + STRING$(jj&& - 1, "0")
        END IF

        z$ = "": zz$ = ""

    LOOP UNTIL h&& >= LEN(b$)

    z$ = holdaa$

    IF decimal% THEN
        DO UNTIL LEN(z$) >= dec_a&& + dec_b&&
            z$ = "0" + z$
        LOOP

        z$ = MID$(z$, 0, LEN(z$) - (dec_a&& + dec_b&& - 1)) + "." + MID$(z$, LEN(z$) - (dec_a&& + dec_b&&) + 1)

        DO UNTIL RIGHT$(z$, 1) <> "0" AND RIGHT$(z$, 1) <> "."
            z$ = MID$(z$, 1, LEN(z$) - 1)
        LOOP
    END IF

    IF STRING$(LEN(z$), "0") = z$ OR z$ = "" OR z$ = "0" THEN z$ = "0" ELSE z$ = sign$ + z$

    decimal% = 0: sign$ = ""

    runningtotal$ = z$
    sm_mult$ = z$
END FUNCTION

FUNCTION sm_div$ (stringmatha$, stringmathb$)
    hold_stringmatha$ = stringmatha$: hold_stringmathb$ = stringmathb$
    q$ = "": divisor$ = stringmathb$: dividend$ = stringmatha$
    DO ' Falx loop.
        'Strip off neg(s) and determine quotent sign.
        IF LEFT$(divisor$, 1) = "-" THEN divisor$ = MID$(divisor$, 2): q$ = "-"
        IF LEFT$(dividend$, 1) = "-" THEN dividend$ = MID$(dividend$, 2): IF q$ = "-" THEN q$ = "" ELSE q$ = "-"

        ' Quick results for divisor 1 or 0.
        IF dividend$ = "0" THEN q$ = "0": EXIT DO
        IF divisor$ = "1" THEN q$ = dividend$: EXIT DO
        IF divisor$ = "0" THEN q$ = "Division by zero not possible.": EXIT DO

        ' Determine decimal direction. -1 to left, +1 to right.
        gl% = 0: sm_greater_lesser divisor$, dividend$, gl%
        IF betatest% AND gl% = 1 THEN PRINT divisor$; " > "; dividend$; " Move decimal to the left"
        IF betatest% AND gl% = 0 THEN PRINT divisor$; " = "; dividend$
        IF betatest% AND gl% = -1 THEN PRINT divisor$; " < "; dividend$; " Move deciml to the right."
        IF gl% = 1 THEN ' Divisor is larger than dividend so decimal moves to the left.
            div_decimal% = -1 ' Move decimal point to the left.
        ELSEIF gl% = -1 THEN
            div_decimal% = 1 ' Move decimal point to the right.
        ELSE
            ' Divisor and dividend are the same number.
            q$ = q$ + "1": EXIT DO
        END IF
        divisor_ratio_dividend% = gl%

        ' Strip off decimal point(s) and determine places in these next 2 routines.
        dp&& = 0: dp2&& = 0: j2&& = 0
        temp&& = INSTR(divisor$, ".")
        IF temp&& THEN
            divisor$ = MID$(divisor$, 1, temp&& - 1) + MID$(divisor$, temp&& + 1)
            IF temp&& = 1 THEN
                DO UNTIL LEFT$(divisor$, 1) <> "0" ' Strip off any leading zeros on divisor only.
                    divisor$ = MID$(divisor$, 2)
                    dp&& = dp&& + 1
                LOOP
                dp&& = dp&& + 1
            ELSE
                dp&& = -(temp&& - 2)
            END IF
        ELSE
            dp&& = -(LEN(divisor$) - 1)
        END IF
        temp&& = INSTR(dividend$, ".")
        IF temp&& THEN
            dividend$ = MID$(dividend$, 1, temp&& - 1) + MID$(dividend$, temp&& + 1)
            IF temp&& = 1 THEN
                DO UNTIL LEFT$(dividend$, 1) <> "0" ' Strip off any leading zeros on divisor only.
                    dividend$ = MID$(dividend$, 2)
                    dp2&& = dp2&& + 1
                LOOP
                dp2&& = dp2&& + 1
            ELSE
                dp2&& = -(temp&& - 2)
            END IF
        ELSE
            dp2&& = -(LEN(dividend$) - 1)
        END IF
        IF betatest% THEN COLOR 11: PRINT "Divisor decimal moves "; LTRIM$(STR$(dp&&)); ". Dividend decimal moves"; LTRIM$(STR$(dp2&&)); ". Quotent decimal ABS("; LTRIM$(STR$(dp&&)); " - "; LTRIM$(STR$(dp2&&)); ") =";: COLOR 14: PRINT ABS(dp&& - dp2&&);: COLOR 11: PRINT "+ any adjustment.": COLOR 7
        dp&& = ABS(dp&& - dp2&&)

        IF betatest% THEN PRINT "Divisor 1st# = "; MID$(divisor$, 1, 1); "  Remainder 1st# = "; MID$(dividend$, 1, 1)

        ' Adjust decimal place for instances when divisor is larger than remainder the length of the divisor.
        j% = 0
        IF MID$(divisor$, 1, 1) > MID$(dividend$, 1, 1) THEN
            j% = 1
            IF betatest% THEN PRINT "Larger divisor, so move quotent decimal one place back to: ";: COLOR 14: PRINT LTRIM$(STR$(dp&&)): COLOR 7
        ELSEIF MID$(divisor$, 1, 1) = MID$(dividend$, 1, 1) THEN
            IF LEN(divisor$) = LEN(dividend$) THEN
                IF divisor$ > dividend$ THEN j% = 1
            ELSE
                IF LEN(divisor$) > LEN(dividend$) THEN
                    temp$ = dividend$ + STRING$(LEN(divisor$) - LEN(dividend$), "0")
                ELSE
                    temp$ = MID$(dividend$, 1, LEN(divisor$))
                END IF
                IF divisor$ > temp$ THEN j% = 1
            END IF
            IF j% THEN
                dp&& = dp&& - div_decimal%
                IF betatest% THEN PRINT "Larger divisor than dividend at LEN(divisor$), so move quotent decimal one place back to: ";: COLOR 14: PRINT LTRIM$(STR$(dp&&)): COLOR 7
            ELSE
                IF betatest% THEN PRINT "Smaller divisor than dividend at LEN(divisor$), so no quotent decimal place adjustment needed. Quotent decimal place = ";: COLOR 14: PRINT LTRIM$(STR$(dp&&)): COLOR 7
            END IF
        ELSE
            j% = 0
            IF betatest% THEN PRINT "Smaller divisor, so no quotent decimal place adjustment needed. Quotent decimal place = ";: COLOR 14: PRINT LTRIM$(STR$(dp&&)): COLOR 7
        END IF
        IF j% THEN dp&& = dp&& - div_decimal%

        origdividend$ = dividend$
        ' Determine length of divisor and dividend to begin initial long divison step.
        gl% = 2: sm_greater_lesser divisor$, MID$(dividend$, 1, LEN(divisor$)) + STRING$(LEN(divisor$) - LEN(dividend$), "0"), gl%
        divisor_ratio_dividend% = gl%
        IF gl% = 1 AND MID$(dividend$, 1, 1) <> "0" THEN
            dividend$ = MID$(dividend$, 1, LEN(divisor$) + 1) + STRING$(LEN(divisor$) + 1 - LEN(dividend$), "0")
        ELSE
            dividend$ = MID$(dividend$, 1, LEN(divisor$)) + STRING$(LEN(divisor$) - LEN(dividend$), "0")
        END IF

        ' Long divison loop. Mult and subtraction of dividend and remainder.
        k&& = 0
        IF betatest% THEN PRINT "Begin long divison loop..."
        DO
            SELECT CASE MID$(divisor$, 1, 1)
                CASE IS < MID$(dividend$, 1, 1)
                    adj_rem_len% = 0
                CASE IS = MID$(dividend$, 1, 1)
                    gl% = 2: sm_greater_lesser divisor$, MID$(dividend$, 1, LEN(divisor$)), gl%
                    IF gl% = 1 THEN adj_rem_len% = 1 ELSE adj_rem_len% = 0
                CASE IS > MID$(dividend$, 1, 1)
                    adj_rem_len% = 1
            END SELECT
            IF j2&& = 0 THEN j2&& = LEN(divisor$) + adj_rem_len%
            DO
                IF LEN(divisor$) > LEN(dividend$) THEN
                    w3&& = 0: runningtotal$ = dividend$: stringmathb$ = "0"
                    IF betatest% THEN PRINT: COLOR 3: PRINT "Divisor is larger so "; dividend$; " \ "; divisor$; " =";: COLOR 5: PRINT w3&&: COLOR 7
                    EXIT DO
                END IF
                IF LEN(divisor$) = LEN(dividend$) THEN
                    gl% = 2: sm_greater_lesser divisor$, dividend$, gl%
                    IF gl% = 1 THEN
                        w3&& = 0: runningtotal$ = dividend$: stringmathb$ = "0"
                        IF betatest% THEN COLOR 9: PRINT "Length of divisor is the same as remainder but remainder is smaller so w3&& = ";: COLOR 5: PRINT "0": COLOR 7
                        EXIT DO
                    END IF
                END IF
                SELECT CASE LEN(dividend$)
                    CASE IS > 2
                        w3&& = VAL(MID$(dividend$, 1, 2 + adj_rem_len%)) \ VAL(MID$(divisor$, 1, 2))
                        IF betatest% THEN PRINT MID$(dividend$, 1, 2 + adj_rem_len%); " \ "; MID$(divisor$, 1, 2); " =";
                    CASE ELSE
                        w3&& = VAL(MID$(dividend$, 1, 1 + adj_rem_len%)) \ VAL(MID$(divisor$, 1, 1))
                        IF betatest% THEN PRINT MID$(dividend$, 1, 1 + adj_rem_len%); " \ "; MID$(divisor$, 1, 1); " =";
                END SELECT
                IF betatest% THEN COLOR 5: PRINT " " + LTRIM$(STR$(w3&&));: COLOR 7: PRINT ". Begin mult est. at or one above this number."
                IF w3&& < 9 THEN w3&& = w3&& + 1 ELSE IF w3&& = 10 THEN w3&& = 9
                DO
                    stringmatha$ = divisor$: stringmathb$ = LTRIM$(STR$(w3&&))
                    runningtotal$ = sm_mult$(divisor$, LTRIM$(STR$(w3&&)))
                    gl% = 2: sm_greater_lesser runningtotal$, dividend$, gl%
                    IF gl% <= 0 OR w3&& = 0 THEN EXIT DO
                    IF betatest% THEN COLOR 8: PRINT "Mult loop:"; w3&&; "* "; divisor$; " = "; runningtotal$: COLOR 7
                    w3&& = w3&& - 1
                LOOP
                stringmatha$ = dividend$: stringmathb$ = runningtotal$
                sm_add_subtract_router dividend$, "-", stringmathb$, runningtotal$
                EXIT DO
            LOOP
            IF betatest% THEN PRINT LTRIM$(STR$(w3&&)); " * "; divisor$; " = "; stringmathb$; " | "; stringmatha$; " - "; stringmathb$; " = "; runningtotal$; " Remainder and drop-down = ";
            j2&& = j2&& + 1
            drop$ = "0": MID$(drop$, 1, 1) = MID$(origdividend$, j2&&, 1)
            IF runningtotal$ <> "0" THEN remainder$ = runningtotal$ ELSE remainder$ = ""
            dividend$ = remainder$ + drop$
            w3$ = LTRIM$(STR$(w3&&))
            temp$ = ""
            IF div_decimal% = -1 THEN
                IF dp&& AND k&& = 0 THEN
                    q$ = q$ + "." + STRING$(dp&& - 1, "0")
                    IF w3&& = 0 THEN w3$ = ""
                END IF
            END IF
            IF div_decimal% >= 0 THEN
                IF dp&& = k&& THEN
                    temp$ = "."
                END IF
            END IF
            q$ = q$ + w3$ + temp$
            IF betatest% AND remainder$ = "" THEN betatemp$ = CHR$(34) + CHR$(34) ELSE IF betatest% THEN betatemp$ = remainder$
            IF betatest% AND MID$(origdividend$, j2&&, 1) = "" THEN betatemp2$ = CHR$(34) + CHR$(34) ELSE IF betatest% THEN betatemp2$ = MID$(origdividend$, j2&&, 1)
            IF betatest% THEN PRINT dividend$; " ("; betatemp$; " +  "; drop$; ") at:"; j2&&; "of "; origdividend$; "  Loop"; k&& + 1; "Quotent = ";: COLOR 14, 4: PRINT q$;: COLOR 7, 0: PRINT: SLEEP
            ' Check to terminate
            IF div_decimal% = -1 THEN
                ' Decimal to left.
                IF remainder$ = "" AND MID$(origdividend$, j2&&, 1) = "" OR LEN(q$) >= limit&& THEN EXIT DO
            ELSE
                ' Decimal to right.
                IF remainder$ = "" AND MID$(origdividend$, j2&&, 1) = "" AND k&& >= dp&& OR LEN(q$) >= limit&& THEN EXIT DO
            END IF

            IF INKEY$ = " " THEN EXIT DO
            k&& = k&& + 1
        LOOP
        EXIT DO
    LOOP
    IF RIGHT$(q$, 1) = "." AND divisor$ <> "0" THEN runningtotal$ = MID$(q$, 1, LEN(q$) - 1) ELSE runningtotal$ = q$
    sm_div$ = runningtotal$
    stringmatha$ = hold_stringmatha$: stringmathb$ = hold_stringmathb$
END FUNCTION

Pete
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#28
@Pete - Why don't you buy the damn book? I'm sure this would be a treasure trove for such a math freak like you.

Formelsammlung zur numerischen Mathematik mit Quick Basic-Programmen

Description
Reply
#29
Kernelpanic, here's an interesting book NUMERICAL MATHEMATICS AND COMPUTING by Ward Cheney and David Kincaid
Reply
#30
German math? No thanks. It's like the old saying goes... There are only two types of German cars. The ones in the shop, and the ones going to the shop.

Other than that, it isn't available for shipping in my region, the center of the universe.

Pete Big Grin
If eggs are brain food, Biden takes his scrambled.
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