From 40f16f2d2155bde6a6cc00d9946a7a424aae36d9 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Fri, 27 Apr 2018 16:20:23 +0200
Subject: bicgstab: make the number of iterations runtime-configurable

---
 bicgstab.c | 11 ++++++-----
 bicgstab.h |  2 +-
 pssolve.c  |  2 +-
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/bicgstab.c b/bicgstab.c
index 9b4d330..ab3e862 100644
--- a/bicgstab.c
+++ b/bicgstab.c
@@ -31,11 +31,11 @@
 #include "bicgstab.h"
 #include "common.h"
 
-#define BICGSTAB_MAXITER 16
 #define BICGSTAB_TOL (1e-15)
 
 struct BiCGStabContext {
     int N;
+    int maxiter;
 
     double *x;
     double *p, *v, *y, *z, *t;
@@ -164,7 +164,7 @@ static int solve_cl(BiCGStabContext *ctx,
 
         rho_prev = rho;
     }
-    if (i == BICGSTAB_MAXITER)
+    if (i == ctx->maxiter)
         return -1;
 
     clEnqueueReadBuffer(ocl_q, ctx->cl_x, 1, 0, sizeof(double) * N,
@@ -200,7 +200,7 @@ static int solve_sw(BiCGStabContext *ctx,
     memcpy(res0, res, N * sizeof(*res0));
     memcpy(p,    res, N * sizeof(*p));
 
-    for (i = 0; i < BICGSTAB_MAXITER; i++) {
+    for (i = 0; i < ctx->maxiter; i++) {
         rho = cblas_ddot(N, res, 1, res0, 1);
 
         if (i) {
@@ -239,7 +239,7 @@ static int solve_sw(BiCGStabContext *ctx,
 
         rho_prev = rho;
     }
-    if (i == BICGSTAB_MAXITER)
+    if (i == ctx->maxiter)
         return -1;
 
     memcpy(x, ctx->x, sizeof(*x) * ctx->N);
@@ -298,7 +298,7 @@ int tdi_bicgstab_init(BiCGStabContext *ctx, const double *k, const double *x0)
     return 0;
 }
 
-int tdi_bicgstab_context_alloc(BiCGStabContext **pctx, int N,
+int tdi_bicgstab_context_alloc(BiCGStabContext **pctx, int N, int maxiter,
                                cl_context ocl_ctx, cl_command_queue ocl_q)
 {
     BiCGStabContext *ctx;
@@ -309,6 +309,7 @@ int tdi_bicgstab_context_alloc(BiCGStabContext **pctx, int N,
         return -ENOMEM;
 
     ctx->N = N;
+    ctx->maxiter = maxiter;
 
 #if HAVE_OPENCL
     if (ocl_ctx) {
diff --git a/bicgstab.h b/bicgstab.h
index 338a4a9..cecc06d 100644
--- a/bicgstab.h
+++ b/bicgstab.h
@@ -36,7 +36,7 @@ typedef struct BiCGStabContext BiCGStabContext;
  * If the OpenCL context and command queue are provided (non-NULL), the solver
  * will run using clBLAS.
  */
-int tdi_bicgstab_context_alloc(BiCGStabContext **ctx, int N,
+int tdi_bicgstab_context_alloc(BiCGStabContext **ctx, int N, int maxiter,
                                cl_context ocl_ctx, cl_command_queue ocl_q);
 
 /**
diff --git a/pssolve.c b/pssolve.c
index f2288c2..906ec00 100644
--- a/pssolve.c
+++ b/pssolve.c
@@ -406,7 +406,7 @@ int tdi_pssolve_context_init(PSSolveContext *ctx)
     s->steps_since_inverse = INT_MAX;
 
     /* init the BiCGStab solver */
-    ret = tdi_bicgstab_context_alloc(&s->bicgstab, N, ctx->ocl_ctx, ctx->ocl_queue);
+    ret = tdi_bicgstab_context_alloc(&s->bicgstab, N, 64, ctx->ocl_ctx, ctx->ocl_queue);
     if (ret < 0)
         return ret;
 
-- 
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