All Forums  Origin Forum  Origin Forum  Trouble of using complex numbers for fitting eqs

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Screensize: 640 x 480 800 x 600 1024 x 768 1280 x 1024 UserName: Password: Anti-Spam Code: Format Mode: Basic  Help  Prompt  Format: Font Andale Mono Arial Arial Black Book Antiqua Century Gothic Comic Sans MS Courier New Georgia Impact Lucida Console Script MT Bold Stencil Tahoma Times New Roman Trebuchet MS Verdana   Size 1 2 3 4 5 6   Color Black Red Yellow Pink Green Orange Purple Blue Beige Brown Teal Navy Maroon LimeGreen Message: * HTML is OFF * Forum Code is ON Smilies [quote][i]Originally posted by jbc1055[/i] [br]Origin Ver. 8.5.1 and Service Release (Select Help-->About Origin): Operating System: Windows 8.1 Hi, I tried to build a equation in origin C for data fitting, but I am having trouble while performing quick check. I noticed that a variable is a complex number (f in the function body), so I used Re() in the final equation to fix that but it seems not working. The data values of x vary from 0 toward negative values, and the corresponding y values should be positive. I tried using some random x values such as -0.01 for quick check, but the calculated y always shows y = --. I was wondering if anyone could teach me how to fix this issue. Thanks in advance! ------ Independent variables: x Dependent variables: y Parameters: A Function body: double d; complex f; d = exp(-75.287*x); f = 0.5*pi*(1/(1-d^2))^0.5 - atan(d/(1-d^2)^0.5)/(1-d^2)^0.5; y = 3.1652e-10*A*Re(f); [/quote]   Check here to include your profile signature. Check here to subscribe to this topic.