diff --git a/examples/recursive_matmul.cxx b/examples/recursive_matmul.cxx
index 7f198160..daf63fea 100644
--- a/examples/recursive_matmul.cxx
+++ b/examples/recursive_matmul.cxx
@@ -22,7 +22,7 @@ void recursive_matmul(int        n,
   MPI_Comm_rank(pcomm, &rank);
   MPI_Comm_size(pcomm, &num_pes);
 
-  if (num_pes == 1){
+  if (num_pes == 1 || m == 1 || n == 1 || k==1){
     C["ij"] += 1.0*A["ik"]*B["kj"];
   } else {
     for (div=2; num_pes%div!=0; div++){}
diff --git a/scalapack_tests/svd.cxx b/scalapack_tests/svd.cxx
index 434fa097..74e018e9 100644
--- a/scalapack_tests/svd.cxx
+++ b/scalapack_tests/svd.cxx
@@ -30,9 +30,9 @@ bool svd(Matrix<dtype> A,
 
   bool pass_orthogonality = true;
 
-  double nrm;
-  E.norm2(nrm);
-  if (nrm > m*n*1.E-6){
+  double nrm1, nrm2, nrm3;
+  E.norm2(nrm1);
+  if (nrm1 > m*n*1.E-6){
     pass_orthogonality = false;
   }
 
@@ -40,16 +40,16 @@ bool svd(Matrix<dtype> A,
 
   E["ij"] -= VT["ik"]*conj<dtype>(VT)["jk"];
 
-  E.norm2(nrm);
-  if (nrm > m*n*1.E-6){
+  E.norm2(nrm2);
+  if (nrm2 > m*n*1.E-6){
     pass_orthogonality = false;
   }
 
   A["ij"] -= U["ik"]*S["k"]*VT["kj"];
 
   bool pass_residual = true;
-  A.norm2(nrm);
-  if (nrm > m*n*n*1.E-6){
+  A.norm2(nrm3);
+  if (nrm3 > m*n*n*1.E-6){
     pass_residual = false;
   }
 
@@ -57,6 +57,12 @@ bool svd(Matrix<dtype> A,
   if (dw.rank == 0){
     printf("SVD orthogonality check returned %d, residual check %d\n", pass_orthogonality, pass_residual);
   }
+#else
+  if (!pass_residual || ! pass_orthogonality){
+    if (dw.rank == 0){
+      printf("SVD orthogonality check returned %d (%lf, %lf), residual check %d (%lf)\n", pass_orthogonality, nrm1, nrm2, pass_residual, nrm3);
+    }
+  }
 #endif
   return pass_residual & pass_orthogonality;
 } 
diff --git a/src/contraction/contraction.cxx b/src/contraction/contraction.cxx
index cc6603ba..06d37bb7 100644
--- a/src/contraction/contraction.cxx
+++ b/src/contraction/contraction.cxx
@@ -2475,14 +2475,12 @@ namespace CTF_int {
   #else
       for (int t=global_comm.rank+1; t<(int)wrld->topovec.size()+8; t+=global_comm.np){
   #endif
-        TAU_FSTART(evaluate_mappings_clear_and_init);
         A->clear_mapping();
         B->clear_mapping();
         C->clear_mapping();
         A->set_padding();
         B->set_padding();
         C->set_padding();
-        TAU_FSTOP(evaluate_mappings_clear_and_init);
       
         topology * topo_i = NULL;
         if (t < 8){
@@ -2511,9 +2509,7 @@ namespace CTF_int {
         } else topo_i = wrld->topovec[t-8];
         ASSERT(topo_i != NULL);
       
-        TAU_FSTART(map_ctr_to_topo);
         ret = map_to_topology(topo_i, j);
-        TAU_FSTOP(map_ctr_to_topo);
 
         if (ret == NEGATIVE){
           //printf("map_to_topology returned negative\n");
@@ -2527,18 +2523,13 @@ namespace CTF_int {
         B->topo = topo_i;
         C->topo = topo_i;
         
-        TAU_FSTART(check_ctr_mapping);
         if (check_mapping() == 0){ 
-          TAU_FSTOP(check_ctr_mapping);
           continue;
         }
-        TAU_FSTOP(check_ctr_mapping);
         est_time = 0.0;
-        TAU_FSTART(evaluate_mappings_set_padding2);
         A->set_padding();
         B->set_padding();
         C->set_padding();
-        TAU_FSTOP(evaluate_mappings_set_padding2);
   #if DEBUG >= 3
         if (global_comm.rank == 0){
           printf("\nTest mappings:\n");
@@ -2565,8 +2556,14 @@ namespace CTF_int {
           }
           nnz_frac_C = std::min(1.,std::max(nnz_frac_C,nnz_frac_A*nnz_frac_B*len_ctr));
         }
+        // check this early on to avoid 64-bit integer overflow
+        double size_memuse = A->size*nnz_frac_A*A->sr->el_size + B->size*nnz_frac_B*B->sr->el_size + C->size*nnz_frac_C*C->sr->el_size;
+        if (size_memuse >= (double)max_memuse){
+          if (global_comm.rank == 0)
+            DPRINTF(1,"Not enough memory available for topo %d with order %d to store tensors %ld/%ld\n", t,j,(int64_t)size_memuse,max_memuse);
+          continue;
+        } 
 
-        TAU_FSTART(evaluate_mappings_folding);
   #if FOLD_TSR
         if (can_fold()){
           est_time = est_time_fold();
@@ -2589,7 +2586,6 @@ namespace CTF_int {
             est_time = sctr->est_time_rec(sctr->num_lyr);
           }
         }
-        TAU_FSTOP(evaluate_mappings_folding);
   #if DEBUG >= 3
         if (global_comm.rank == 0){
           printf("mapping passed contr est_time = %E sec\n", est_time);
@@ -2600,7 +2596,6 @@ namespace CTF_int {
         need_remap_A = 0;
         need_remap_B = 0;
         need_remap_C = 0;
-        TAU_FSTART(evaluate_mappings_comp_maps);
         if (topo_i == old_topo_A){
           for (d=0; d<A->order; d++){
             if (!comp_dim_map(&A->edge_map[d],&old_map_A[d]))
@@ -2631,8 +2626,6 @@ namespace CTF_int {
           }
         } else
           need_remap_C = 1;
-        TAU_FSTOP(evaluate_mappings_comp_maps);
-        TAU_FSTART(est_ctr_map_time);
         if (need_remap_C) {
           est_time += 2.*C->est_redist_time(*dC, nnz_frac_C); 
           memuse = std::max(1.0*memuse,2.*C->get_redist_mem(*dC, nnz_frac_C));
@@ -2646,20 +2639,16 @@ namespace CTF_int {
           printf("total (with redistribution and transp) est_time = %E\n", est_time);
         }
   #endif
-        TAU_FSTOP(est_ctr_map_time);
         ASSERT(est_time >= 0.0);
 
-        TAU_FSTART(get_avail_res);
         if ((int64_t)memuse >= max_memuse){
           if (global_comm.rank == 0)
             DPRINTF(1,"Not enough memory available for topo %d with order %d memory %ld/%ld\n", t,j,memuse,max_memuse);
-          TAU_FSTOP(get_avail_res);
           delete sctr;
           continue;
         } 
         if ((!A->is_sparse && A->size > INT_MAX) ||(!B->is_sparse &&  B->size > INT_MAX) || (!C->is_sparse && C->size > INT_MAX)){
           DPRINTF(1,"MPI does not handle enough bits for topo %d with order\n", j);
-          TAU_FSTOP(get_avail_res);
           delete sctr;
           continue;
         }
@@ -2670,7 +2659,6 @@ namespace CTF_int {
           btopo = 6*t+j;
         }  
         delete sctr;
-        TAU_FSTOP(get_avail_res);
       }
     }
     TAU_FSTOP(evaluate_mappings)
@@ -3509,7 +3497,27 @@ namespace CTF_int {
     }
   #endif
 
-
+    if (blk_sz_A < vrt_sz_A){
+      printf("blk_sz_A = %ld, vrt_sz_A = %ld\n", blk_sz_A, vrt_sz_A);
+      printf("sizes are %ld %ld %ld\n",A->size,B->size,C->size);
+      A->print_map(stdout, 0);
+      B->print_map(stdout, 0);
+      C->print_map(stdout, 0);
+    }
+    if (blk_sz_B < vrt_sz_B){
+      printf("blk_sz_B = %ld, vrt_sz_B = %ld\n", blk_sz_B, vrt_sz_B);
+      printf("sizes are %ld %ld %ld\n",A->size,B->size,C->size);
+      A->print_map(stdout, 0);
+      B->print_map(stdout, 0);
+      C->print_map(stdout, 0);
+    }
+    if (blk_sz_C < vrt_sz_C){
+      printf("blk_sz_C = %ld, vrt_sz_C = %ld\n", blk_sz_C, vrt_sz_C);
+      printf("sizes are %ld %ld %ld\n",A->size,B->size,C->size);
+      A->print_map(stdout, 0);
+      B->print_map(stdout, 0);
+      C->print_map(stdout, 0);
+    }
     ASSERT(blk_sz_A >= vrt_sz_A);
     ASSERT(blk_sz_B >= vrt_sz_B);
     ASSERT(blk_sz_C >= vrt_sz_C);
diff --git a/src/contraction/ctr_2d_general.cxx b/src/contraction/ctr_2d_general.cxx
index 90b016b5..1c5909fb 100755
--- a/src/contraction/ctr_2d_general.cxx
+++ b/src/contraction/ctr_2d_general.cxx
@@ -47,7 +47,7 @@ namespace CTF_int {
                         int &                      load_phase_C){
     mapping * map;
     int j;
-    int nstep = 1;
+    int64_t nstep = 1;
     if (comp_dim_map(&C->edge_map[i_C], &B->edge_map[i_B])){
       map = &B->edge_map[i_B];
       while (map->has_child) map = map->child;
@@ -111,16 +111,24 @@ namespace CTF_int {
                 /virt_blk_len_C[j];
         }
         if (B->edge_map[i_B].type != PHYSICAL_MAP){
+          if (blk_sz_B / nstep == 0) 
+            printf("blk_len_B[%d] = %d, nstep = %ld blk_sz_B = %ld\n",i_B,blk_len_B[i_B],nstep,blk_sz_B);
           blk_sz_B  = blk_sz_B / nstep;
           blk_len_B[i_B] = blk_len_B[i_B] / nstep;
         } else {
+          if (blk_sz_B  * B->edge_map[i_B].np/ nstep == 0) 
+            printf("blk_len_B[%d] = %d  B->edge_map[%d].np = %d, nstep = %ld blk_sz_B = %ld\n",i_B,blk_len_B[i_B],i_B,B->edge_map[i_B].np,nstep,blk_sz_B);
           blk_sz_B  = blk_sz_B * B->edge_map[i_B].np / nstep;
           blk_len_B[i_B] = blk_len_B[i_B] * B->edge_map[i_B].np / nstep;
         }
         if (C->edge_map[i_C].type != PHYSICAL_MAP){
+          if (blk_sz_C / nstep == 0) 
+            printf("blk_len_C[%d] = %d, nstep = %ld blk_sz_C = %ld\n",i_C,blk_len_C[i_C],nstep,blk_sz_C);
           blk_sz_C  = blk_sz_C / nstep;
           blk_len_C[i_C] = blk_len_C[i_C] / nstep;
         } else {
+          if (blk_sz_C  * C->edge_map[i_C].np/ nstep == 0) 
+            printf("blk_len_C[%d] = %d  C->edge_map[%d].np = %d, nstep = %ld blk_sz_C = %ld\n",i_C,blk_len_C[i_C],i_C,C->edge_map[i_C].np,nstep,blk_sz_C);
           blk_sz_C  = blk_sz_C * C->edge_map[i_C].np / nstep;
           blk_len_C[i_C] = blk_len_C[i_C] * C->edge_map[i_C].np / nstep;
         }
diff --git a/src/interface/matrix.cxx b/src/interface/matrix.cxx
index e041d2f0..f68ceeed 100644
--- a/src/interface/matrix.cxx
+++ b/src/interface/matrix.cxx
@@ -213,8 +213,8 @@ namespace CTF {
         if (lda == nrow/pc){
           memcpy(this->data, (char*)data_, sizeof(dtype)*this->size);
         } else {
-          for (int i=0; i<ncol/pc; i++){
-            memcpy(this->data+i*lda*sizeof(dtype),(char*)(data_+i*lda), nrow*sizeof(dtype)/pr);
+          for (int64_t i=0; i<ncol/pc; i++){
+            memcpy(this->data+i*lda*sizeof(dtype),(char*)(data_+i*lda), ((int64_t)nrow)*sizeof(dtype)/pr);
           }
         }
       } else {
@@ -258,7 +258,7 @@ namespace CTF {
         if (lda == nrow/pc){
           memcpy((char*)data_, this->data, sizeof(dtype)*this->size);
         } else {
-          for (int i=0; i<ncol/pc; i++){
+          for (int64_t i=0; i<ncol/pc; i++){
             memcpy((char*)(data_+i*lda), this->data+i*lda*sizeof(dtype), nrow*sizeof(dtype)/pr);
           }
         }
@@ -437,11 +437,11 @@ namespace CTF {
 
     this->read_mat(desca, A);
 
-    dtype * tau = (dtype*)malloc(n*sizeof(dtype));
+    dtype * tau = (dtype*)malloc(((int64_t)n)*sizeof(dtype));
     dtype dlwork;
     CTF_SCALAPACK::pgeqrf<dtype>(m,n,A,1,1,desca,tau,(dtype*)&dlwork,-1,&info);
     int lwork = get_int_fromreal<dtype>(dlwork);
-    dtype * work = (dtype*)malloc(lwork*sizeof(dtype));
+    dtype * work = (dtype*)malloc(((int64_t)lwork)*sizeof(dtype));
     CTF_SCALAPACK::pgeqrf<dtype>(m,n,A,1,1,desca,tau,work,lwork,&info);
  
 
@@ -453,14 +453,14 @@ namespace CTF {
       R = Matrix<dtype>(Q);
     else {
       R = Matrix<dtype>(desca,dQ,*this->wrld,*this->sr);
-      R = R.slice(0,m*(n-1)+n-1);
+      R = R.slice(0,((int64_t)m)*(n-1)+n-1);
     }
 
 
     free(work);
     CTF_SCALAPACK::porgqr<dtype>(m,n,n,dQ,1,1,desca,tau,(dtype*)&dlwork,-1,&info);
     lwork = get_int_fromreal<dtype>(dlwork);
-    work = (dtype*)malloc(lwork*sizeof(dtype));
+    work = (dtype*)malloc(((int64_t)lwork)*sizeof(dtype));
     CTF_SCALAPACK::porgqr<dtype>(m,n,n,dQ,1,1,desca,tau,work,lwork,&info);
     Q = Matrix<dtype>(desca, dQ, (*(this->wrld)));
     free(work);
@@ -502,14 +502,16 @@ namespace CTF {
     int64_t kpr = k/pr + (k % pr != 0);
     int64_t kpc = k/pc + (k % pc != 0);
     int64_t npc = n/pc + (n % pc != 0);
+
     CTF_SCALAPACK::cdescinit(descu, m, k, 1, 1, 0, 0, ictxt, mpr, &info);
     CTF_SCALAPACK::cdescinit(descvt, k, n, 1, 1, 0, 0, ictxt, kpr, &info);
-    dtype * A = (dtype*)malloc(this->size*sizeof(dtype));
+
+    dtype * A = (dtype*)CTF_int::alloc(this->size*sizeof(dtype));
 
 
-    dtype * u = (dtype*)new dtype[mpr*kpc];
-    dtype * s = (dtype*)new dtype[k];
-    dtype * vt = (dtype*)new dtype[kpr*npc];
+    dtype * u = (dtype*)CTF_int::alloc(sizeof(dtype)*mpr*kpc);
+    dtype * s = (dtype*)CTF_int::alloc(sizeof(dtype)*k);
+    dtype * vt = (dtype*)CTF_int::alloc(sizeof(dtype)*kpr*npc);
     this->read_mat(desca, A);
 
     int lwork;
@@ -517,7 +519,7 @@ namespace CTF {
     CTF_SCALAPACK::pgesvd<dtype>('V', 'V', m, n, NULL, 1, 1, desca, NULL, NULL, 1, 1, descu, vt, 1, 1, descvt, &dlwork, -1, &info);  
 
     lwork = get_int_fromreal<dtype>(dlwork);
-    dtype * work = (dtype*)malloc(sizeof(dtype)*lwork);
+    dtype * work = (dtype*)CTF_int::alloc(sizeof(dtype)*((int64_t)lwork));
 
     CTF_SCALAPACK::pgesvd<dtype>('V', 'V', m, n, A, 1, 1, desca, s, u, 1, 1, descu, vt, 1, 1, descvt, work, lwork, &info);	
 
@@ -537,18 +539,18 @@ namespace CTF {
     }
     if (rank > 0 && rank < k) {
       S = S.slice(0, rank-1);
-      U = U.slice(0, rank*(m)-1);
-      VT = VT.slice(0, k*n-(k-rank+1));
+      U = U.slice(0, rank*((int64_t)m)-1);
+      VT = VT.slice(0, k*((int64_t)n)-(k-rank+1));
     }
 
-    free(A);
-    delete [] u;
-    delete [] s;
-    delete [] vt;
+    CTF_int::cdealloc(A);
+    CTF_int::cdealloc(u);
+    CTF_int::cdealloc(s);
+    CTF_int::cdealloc(vt);
     free(desca);
     free(descu);
     free(descvt);
-    free(work);
+    CTF_int::cdealloc(work);
 
   }