function [xnew,gradnew,alpha,p] = steepdesc(searchmtd,fnhess,fngrad,fn,gradold,xold)
% description: does a single step of steepest descent. Returns
% new x value, its gradient, step length and direction.
% Input paramters:
% searchmtd: line search method
% fnhess: function hessian name
% fngrad: function grad name
% fn: function name
% gradold: gradient at starting point
% xold: starting point

% global variables:
global parms;

% local variables:
% xnew: new x value
% gradnew: gradf(xnew)
% alpha: step length used
% p: descent direction used

p = -gradold;
alpha = feval(searchmtd,fngrad,fn,xold,p);
xnew = xold + alpha*p;
gradnew = feval(fngrad,xnew);