# levmar()

Usage:
 ```levmar(b,x,y [,f],param [,resid:residmac,deriv:deriv,crit:crvec,\ active:active,maxit:itmax,minit:itmin,print:T]) b REAL vector of starting values for coefficients x REAL variable, usually a vector or matrix with nrows(x) = nrows(y) y REAL vector of data to be fit f macro called as fit <- f(b,x,param) param vector or structure of additional parameters for f or NULL residmac A macro called as residmac(b, x, y, param) to compute a vector of residuals of length nrows(y). When f is an argument, 'resid' should not be used and residmac(b,x,y,param) is essentially y - f(b,x,param) crvect vector(numsig, nsigsq, delta), 3 criteria for convergence deriv optional macro; deriv(b,x,y,param,j) computes derivative of f with respect to b[j] active LOGICAL vector the same length as b itmax maximum number of iterations permitted (default 30) itmin minimum number of iterations performed (default 1) print if T, partial results are printed on each iteration returns structure(coefs,hessian,jacobian,gradient,rss,residuals, nobs, iter, iconv) ```

Keywords: nonlinear fitting
```Proper help has not been written yet.  Here are comments from the
macro file.

Macro for fitting functions or estimating parameters by minimizing
sums of squares of residuals.

Usage:
levmar(b,x,y [,f],param [,resid:residmac,deriv:deriv,crit:crvec,\
active:active,maxit:itmax,minit:itmin,print:T])
b        REAL vector of starting values for coefficients
x        REAL variable, usually a vector or matrix with nrows(x) =
nrows(y)
y        REAL vector of data to be fit
f        macro called as fit <- f(b,x,param)
param    vector or structure of additional parameters for f or NULL
residmac A macro called as residmac(b, x, y, param) to compute a vector
of residuals of length nrows(y).  When f is an argument,
'resid' should not be used and residmac(b,x,y,param) is
essentially y - f(b,x,param)
crvect   vector(numsig, nsigsq, delta), 3 criteria for convergence
controlling the desired accuracy of coefficients and of the
the residual sum of squares, and a target size for the norm
deriv    optional macro; deriv(b,x,y,param,j) computes derivative of
f with respect to b[j]
active   LOGICAL vector the same length as b.  b[j] "participates"
in the iteration only if active[j] is True (default is
rep(T,length(b)))

itmax    maximum number of iterations permitted (default 30)
itmin    minimum number of iterations performed (default 1)
print    if T, partial results are printed on each iteration