SCULIB_MRQCOF

Utility routine called by SCULIB_MRQMIN, copied from Numerical Recipes in Fortran, p. 681. Used by SCULIB_MRQMIN to evaluate the linearised fitting matrix ALPHA, and vector BETA, and calculate chi-squared. Copied from MRQCOF on p.681 of Numerical Recipes in Fortran, with STATUS added.

CALL SCULIB_MRQCOF (X, Y, SIG, NDATA, A, IA, MA, ALPHA, BETA, NALP, CHISQ, FUNCS, STATUS)

X( NDATA ) = REAL (Given)

X Data points

Y( NDATA ) = REAL (Given)

Y data points

SIG ( NDATA ) = REAL (Given)

NDATA = INTEGER (Given)

Number of data points in arrays

A( MA ) = REAL (Given & Returned)

The input parameter values. Contains the best-fit values on exit.

IA( MA ) = INTEGER (Given)

Array specifying which components should be fitted. A zero indicates the parameter should not be fitted – the parameters are kept at their input values. Non-zero indicates the parameter is free to be modified.

MA = INTEGER (Given)

Number of coefficients/parameters for function.

ALPHA( NALP, NALP ) = REAL (Returned)

BETA( MA ) = REAL (Returned)

NALP = INTEGER (Given)

Size of ALPHA.

CHISQ = REAL (Returned)

ChiSq of fit.

FUNCS = REAL FUNCTION (Given)

The function to be fitted. Must take arguments of X, A, YFIT, DYDA and MA, where YFIT is the fitting function and DYDA the the derivatives with respect to parameters A at X.

STATUS = INTEGER (Given & Returned)

Global Status