Replaced arraySync with slice + concat

tfjs-core/src/ops/linalg_ops.ts

@@ -28,7 +28,7 @@ import {split} from './concat_split';
 import {norm} from './norm';
 import {op} from './operation';
 import {sum} from './reduction_ops';
-import {tensor, tensor2d} from './tensor_ops';
+import {tensor, tensor1d, tensor2d} from './tensor_ops';
 
 /**
  * Copy a tensor setting everything outside a central band in each innermost
@@ -71,7 +71,8 @@ function bandPart_(x: Tensor, numLower: number, numUpper: number): Tensor {
     if (totalElements === 0) {
       return tensor([], x.shape);
     }
-    const parted: number[] = x.flatten().arraySync();
+    const flattened: Tensor1D = x.flatten();
+    let band: Tensor1D = tensor1d([]);
     const rows = (x.rank < 2) ? 1 : x.shape[x.rank - 2];
     const cols = x.shape[x.rank - 1];
 
@@ -80,12 +81,14 @@ function bandPart_(x: Tensor, numLower: number, numUpper: number): Tensor {
         for (let k = 0; k < cols; ++k) {
           if ((numLower > -1 && k < j - numLower) ||
               (numUpper > -1 && k > j + numUpper)) {
-            parted[i + j * rows + k] = 0;
+            band = band.concat(tensor([0]));
+          } else {
+            band = band.concat(flattened.slice(i + j * rows + k, 1));
           }
         }
       }
     }
-    return tensor(parted, x.shape);
+    return band.reshape(x.shape);
   });
 }