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lamp_mac/DIF/

rect_funct.pro


NAME: RECT_FUNCT PURPOSE: EVALUATE THE SUM OF A CONVOLUTION OF A GAUSSIAN AND A RECTANGLE AND A 2ND ORDER POLYNOMIAL AND OPTIONALLY RETURN THE VALUE OF IT'S PARTIAL DERIVATIVES. NORMALLY, THIS FUNCTION IS USED BY CURVEFIT TO FIT THE SUM OF A LINE AND A VARYING BACKGROUND TO ACTUAL DATA. CATEGORY: E2 - CURVE AND SURFACE FITTING. CALLING SEQUENCE: FUNCT,X,A,F,PDER INPUTS: X = VALUES OF INDEPENDENT VARIABLE. A = PARAMETERS OF EQUATION DESCRIBED BELOW. OUTPUTS: F = VALUE OF FUNCTION AT EACH X(I). OPTIONAL OUTPUT PARAMETERS: PDER = (N_ELEMENTS(X),7) ARRAY CONTAINING THE PARTIAL DERIVATIVES. P(I,J) = DERIVATIVE AT ITH POINT W/RESPECT TO JTH PARAMETER. COMMON BLOCKS: NONE. SIDE EFFECTS: NONE. RESTRICTIONS: NONE. PROCEDURE: F = A(0)*EZ + A(4) + A(5)*X + A(6)*X^2 EZ= (ERF(Dp)-ERF(Dm))/(2*A(3)) Dp =(AA+CC)*BB Dm =(AA-CC)*BB AA =X-A(1) BB =2*SQRT(ALOG(2))/A(2) CC =A(3)/2 Elements beyond A(3) are optional. MODIFICATION HISTORY: WRITTEN, DMS, RSI, SEPT, 1982. Modified, DMS, Oct 1990. Avoids divide by 0 if A(2) is 0. Added to Gauss_fit, when the variable function name to Curve_fit was implemented. DMS, Nov, 1990. GAUSS_FUNCT modified to RECT_FUNCT, GAUSSFIT modified to RECTFIT. TCH, ILL, JAN, 2003.

top RECT_FUNCT

RECT_FUNCT, X, A, F, PDER

Parameters

X
A
F
PDER

File attributes

Modification date: Tue Oct 1 14:42:22 2013
Lines: 83