# HG changeset patch
# User Chris Cannam
# Date 1367754102 -3600
# Node ID fd16551c2fc85afcfd5de3e77e6bffebb57d04f5
# Parent  479a739c99b148adc8ff9f8745ba4376fdcb741f
Implement and test rowSlice, columnSlice

diff -r 479a739c99b1 -r fd16551c2fc8 yetilab/matrix/matrix.yeti
--- a/yetilab/matrix/matrix.yeti	Sun May 05 12:41:29 2013 +0100
+++ b/yetilab/matrix/matrix.yeti	Sun May 05 12:41:42 2013 +0100
@@ -195,7 +195,8 @@
         failWith "Matrix dimensions incompatible for concat (found \(map do m: counter m.size done mm) not all of which are \(n))";
     fi);
 
-concat direction mm = //!!! storage order is taken from first matrix in sequence
+concat direction mm = //!!! doc: storage order is taken from first matrix in sequence
+    //!!! would this be better as separate concatHorizontal/concatVertical functions?
     if empty? mm then zeroSizeMatrix ()
     else
         first = head mm;
@@ -217,6 +218,20 @@
         esac;
     fi;
 
+rowSlice start count m = //!!! doc: storage order same as input
+    if m.isRowMajor? then
+        make (RowM (array (map (block.data . m.getRow) [start .. start + count - 1])))
+    else 
+        make (ColM (array (map (block.data . (block.rangeOf start count)) (asColumns m))))
+    fi;
+
+columnSlice start count m = //!!! doc: storage order same as input
+    if not m.isRowMajor? then
+        make (ColM (array (map (block.data . m.getColumn) [start .. start + count - 1])))
+    else 
+        make (RowM (array (map (block.data . (block.rangeOf start count)) (asRows m))))
+    fi;
+
 {
 constMatrix, randomMatrix, zeroMatrix, identityMatrix, zeroSizeMatrix,
 generate,
@@ -230,6 +245,7 @@
 asRows, asColumns,
 sum = sum', product,
 concat,
+rowSlice, columnSlice,
 newMatrix, newRowVector, newColumnVector,
 }
 
diff -r 479a739c99b1 -r fd16551c2fc8 yetilab/matrix/test/test_matrix.yeti
--- a/yetilab/matrix/test/test_matrix.yeti	Sun May 05 12:41:29 2013 +0100
+++ b/yetilab/matrix/test/test_matrix.yeti	Sun May 05 12:41:42 2013 +0100
@@ -316,6 +316,18 @@
     yrt
 ),
 
+"rowSlice-\(name)": \(
+    compareMatrices
+       (mat.rowSlice 1 2 (newMatrix (RowMajor ()) [[1,2],[3,4],[5,6],[7,8]]))
+       (newMatrix (RowMajor ()) [[3,4],[5,6]])
+),
+
+"columnSlice-\(name)": \(
+    compareMatrices
+       (mat.columnSlice 1 2 (newMatrix (RowMajor ()) [[1,2,3,4],[5,6,7,8]]))
+       (newMatrix (RowMajor ()) [[2,3],[6,7]])
+),
+
 ]);
 
 colhash = makeTests "column-major" id;