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/* Sample mex function (in MATLAB 5.x format) for getting functions,
   gradients, and sparse Hessians from an AMPL .nl file.  Start with

	[x,bl,bu,v,cl,cu] = spamfunc('stub')

   or, for complementarity problems,

	[x,bl,bu,v,cl,cu,cv] = spamfunc('stub')

   to read in a problem (discarding the previous problem, if any).
   The return values are:

	x = primal initial guess
	v = dual initial guess
	bl, bu = lower and upper bounds on x
	cl, cu = lower and upper bounds on c (the constraint bodies).
	cv variables complementing constraints:  if cv(i) > 0, then
		constraint i complements x(cv(i)); otherwise
		constraint i is an ordinary constraint.

   Then

	[f,c] = spamfunc(x,0)

   gives the function (f) and constraint bodies (c) at x;

	[g,Jac] = spamfunc(x,1)

   gives the gradient g of f, the Jacobian matrix J of c, and

	W = spamfunc(v)

   gives the Hessian W of the Lagrangian function L = f + v*c
   (at the last x at which spamfunc(x,1) was called).

   After finding optimal values for x and v,

	spamfunc('solution message',x,v)

   to write a stub.sol file.
*/

#include "mex.h"
#undef printf

#ifdef _WIN32
/* Omit sw "signal" catching and x86 precision adjustment. */
#define ASL_NO_FP_INIT
#include "fpinit.c"
#endif /* _WIN32 */

#include "asl_pfgh.h"

static char msgbuf[256];

 static real*
sizechk(const mxArray *mp, char *who, fint m)
{
	int m1, n1;
	m1 = mxGetM(mp);
	n1 = mxGetN(mp);
	if (m1 != m || (n1 != 1 && m1)) {
		sprintf(msgbuf,
			"Expected %s to be %d x 1 rather than %d x %d\n",
			who, m, m1, n1);
		mexErrMsgTxt(msgbuf);
		}
	return mxGetPr(mp);
	}

 static void
at_end(void)
{
	if (cur_ASL)
		ASL_free(&cur_ASL);
	}

 static void
usage(void)
{
	mexErrMsgTxt("spamfunc usage:\n\n\
	[x,bl,bu,v,cl,cu] = spamfunc('stub')\nor\n\
	[x,bl,bu,v,cl,cu,cv] = spamfunc('stub')\nor\n\
	[f,c] = spamfunc(x,0)\nor\n\
	[g,Jac] = spamfunc(x,1)\nor\n\
	W = spamfunc(v)\nor\n\
	spamfunc('solution message',x,v)\nor\n\
	spamfunc('solution message',x,v,solve_result_num)\nwith\n\
	x = primal, v = dual variables");
	}

 void
mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
	ASL_pfgh *asl = (ASL_pfgh*)cur_ASL;
	FILE *nl;
	Jmp_buf err_jmp0;
	cgrad *cg, **cgp;
	char *buf1, buf[512], *what, **whatp;
	fint *hcs, *hr, i, nerror;
	int *cs;
	mwIndex *Ir, *Jc;
	real *H, *He, *J1, *W, *c, *f, *g, *v, *t, *x;
	static fint n, nc, nhnz, nz;
	static real *Hsp;
	static char ignore_complementarity[] =
		"Warning: ignoring %d complementarity conditions.\n";

	if (nrhs == 1 && mxIsChar(prhs[0])) {
		if (nlhs < 6 || nlhs > 7)
			usage();
		if (mxGetString(prhs[0], buf1 = buf, sizeof(buf)))
			mexErrMsgTxt("Expected 'stub' as argument\n");
		at_end();
		mexAtExit(at_end);
		asl = (ASL_pfgh*)ASL_alloc(ASL_read_pfgh);
		return_nofile = 1;
		if (!(nl = jac0dim(buf1,strlen(buf)))) {
			sprintf(msgbuf, "Can't open %.*s\n",
				sizeof(msgbuf)-20, buf);
			mexErrMsgTxt(msgbuf);
			}
		if (n_obj <= 0)
			printf("Warning: objectve == 0\n");
		n = n_var;
		nc = n_con;
		nz = nzc;
		X0 = mxGetPr(plhs[0] = mxCreateDoubleMatrix(n, 1, mxREAL));
		LUv = mxGetPr(plhs[1] = mxCreateDoubleMatrix(n, 1, mxREAL));
		Uvx = mxGetPr(plhs[2] = mxCreateDoubleMatrix(n, 1, mxREAL));
		pi0 = mxGetPr(plhs[3] = mxCreateDoubleMatrix(nc, 1, mxREAL));
		LUrhs = mxGetPr(plhs[4] = mxCreateDoubleMatrix(nc, 1, mxREAL));
		Urhsx = mxGetPr(plhs[5] = mxCreateDoubleMatrix(nc, 1, mxREAL));
		if (nlhs == 7) {
			cvar = (int*)M1alloc(nc*sizeof(int));
			plhs[6] = mxCreateDoubleMatrix(nc, 1, mxREAL);
			x = mxGetPr(plhs[6]);
			}
		else if (n_cc)
			printf(ignore_complementarity, n_cc);
		pfgh_read(nl, ASL_findgroups);
		if (nlhs == 7)
			for(i = 0; i < nc; i++)
				x[i] = cvar[i];

		/* Arrange to compute the whole sparese Hessian */
		/* of the Lagrangian function (both triangles). */

		nhnz = sphsetup(0, 0, nc > 0, 0);
		Hsp = (real *)M1alloc(nhnz*sizeof(real));
		return;
		}

	if (!asl)
		mexErrMsgTxt("spamfunc(\"stub\") has not been called\n");
	nerror = -1;
	err_jmp1 = &err_jmp0;
	what = "(?)";
	whatp = &what;
	if (nlhs == 2) {
		if (nrhs != 2)
			usage();
		x = sizechk(prhs[0],"x",n);
		t = sizechk(prhs[1],"0 or 1", 1);
		if (setjmp(err_jmp0.jb)) {
			sprintf(msgbuf, "Trouble evaluating %s\n", *whatp);
			mexErrMsgTxt(msgbuf);
			}
		if (t[0] == 0.) {
			f = mxGetPr(plhs[0] = mxCreateDoubleMatrix(1, 1, mxREAL));
			c = mxGetPr(plhs[1] = mxCreateDoubleMatrix(nc, 1, mxREAL));
			what = "f";
			*f = n_obj > 0 ? objval(0, x, &nerror) : 0;
			what = "c";
			conval(x, c, &nerror);
			return;
			}
		g = mxGetPr(plhs[0] = mxCreateDoubleMatrix(n, 1, mxREAL));
		J1 = mxGetPr(plhs[1] = mxCreateSparse(nc, n, nz, mxREAL));
		what = "g";
		if (n_obj > 0)
			objgrd(0, x, g, &nerror);
		else
			memset(g, 0, n*sizeof(real));
		if (nc) {
			what = "J";
			jacval(x, J1, &nerror);
			Ir = mxGetIr(plhs[1]);
			/*memcpy(mxGetJc(plhs[1]), A_colstarts, (n+1)*sizeof(int));*/
			for(Jc = mxGetJc(plhs[1]), cs = A_colstarts, i = 0; i <= n; ++i)
				Jc[i] = cs[i];
			cgp = Cgrad;
			for(i = 0; i < nc; i++)
				for(cg = *cgp++; cg; cg = cg->next)
					Ir[cg->goff] = i;
			}
		return;
		}
	if (nlhs == 0 && (nrhs == 3 || nrhs == 4)) {
		/* eval2('solution message', x, v): x = primal, v = dual */
		/* optional 4th arg = solve_result_num */
		if (!mxIsChar(prhs[0]))
			usage();
		x = sizechk(prhs[1],"x",n);
		v = sizechk(prhs[2],"v",nc);
		if (mxGetString(prhs[0], buf, sizeof(buf)))
			mexErrMsgTxt(
			 "Expected 'solution message' as first argument\n");
		solve_result_num = nrhs == 3 ? -1 /* unknown */
			: (int)*sizechk(prhs[3],"solve_result_num",1);
		write_sol(buf, x, v, 0);
		return;
		}
	if (nlhs != 1 || nrhs != 1)
		usage();
	v = sizechk(prhs[0],"v",nc);
	W = mxGetPr(plhs[0] = mxCreateSparse(n, n, nhnz, mxREAL));

	what = "W";
	sphes(H = Hsp, 0, 0, v);

	/* Expand the Hessian lower triangle into the full Hessian... */

	Ir = mxGetIr(plhs[0]);
	Jc = mxGetJc(plhs[0]);
	hcs = sputinfo->hcolstarts;
	hr = sputinfo->hrownos;
	for(i = 0; i <= n; i++)
		Jc[i] = hcs[i];
	He = H + hcs[n];
	while(H < He) {
		*W++ = *H++;
		*Ir++ = *hr++;
		}
	}