Complex numbers in excel

[knutso]

I do a call to a sub akoef in the code beneath. It works fine in the
non-complex case that I have coded:

first, the call in main program:

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Call AKOEF(OM, DELT, NAX, G, AKD, a, B)

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here is the called sub - the complex suggestions are in comments:

Sub AKOEF(OM, DELT, NAX, G, AKD, a, B)

i = 1 ' should be -1 for complex
i = Sqr(i) ' should be imsqrt for complex
sa = 0
AKD(NAX) = sa
ARG = Sqr(1 / a) * (-i * OM - 0.5 * OM * (B / a)) * DELT * NAX
s1 = G(NAX) * Exp(ARG) ' exp should be imexp for complex
NA = NAX - 1
For jj = 1 To NA
j = NAX - jj
AKs = AKD(j) * AKD(j)
ARG = Sqr(1 / a) * (i * OM - 0.5 * OM * (B / a)) * DELT * j
s2 = G(j) * Exp(ARG) * (1 - AKS) ' exp should be imexp for complex

sa = 0.5 * (s1 + s2) * DELT + sa
AKD(j) = Exp(-ARG) * sa 'exp should be imexp for complex
s1 = s2
Next jj
End Sub
-----------------------------------------

in FORTRAN the complex case is very simple. I just declare the complex
variables in akoef with a type command like this:

TYPE COMPLEX AKD,AK,AKS,I,CEXP,CSQRT,ARG,S1,S2,SA

I exchange the real function with complex functions. Complex fortran is a
bit different from excel, but the idea is the same.

and the call will return a complex variable AKD.

....so this is no problem..
.... there must be a way to do it simple also in excel. Anyone with experience?

 

[Bernard Liengme]

Open VBA editor and type COMPLEX in the search box
Look at the method called Complex
You should not try to use
i=-1; i=SQR(i)
best wishes