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Date: Sun, 24 Jan 1999 10:26:31 +0900 (JST)
From: gotoken@math.sci.hokudai.ac.jp (GOTO Kentaro)
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Subject: [ruby-ext:00070] MDArray#from_flat
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ごとけんです

伊藤彰則さん作の mdarray にひとつクラスメソッドを足しました．

  mda = MDArray.from_flat(size1,size2, ..., sizeN){ary}

は大雑把に言って次の逆に相当します:

  ary = []; mda.each{|i| ary.push i}

要するに， ary = [e1,e2,...,eM] という平らな配列から，
全部でM個の要素からなるN次元配列 mda を作るものです．
ただし，M == size1 × … × sizeN でなければ例外が
発生します．

pbm(5) を矩形として読むようなときに便利だと思います．
気に入りそうなら使ってください．

# あと，いくつかキャストが抜けてたので足しました．

-- gotoken

diff -u0r ext/mdarray.orig/README ext/mdarray/README
--- ext/mdarray.orig/README	Sun Jan 24 09:36:46 1999
+++ ext/mdarray/README	Sun Jan 24 09:48:12 1999
@@ -80,0 +81,6 @@
+	from_flat(size1, size2, ..., sizeN){array}
+		N次元配列を作り，ブロックを評価した値で初期化します．
+		ブロックを評価した値が配列でなければ例外が発生します．
+		初期化は，array.each の順に取り出され，each の
+		順に代入されます．作ったN次元配列の要素の総数と，
+		array の総数が一致しないときは例外が発生します．
diff -u0r ext/mdarray.orig/mdarray.c ext/mdarray/mdarray.c
--- ext/mdarray.orig/mdarray.c	Tue Aug 26 13:48:13 1997
+++ ext/mdarray/mdarray.c	Sun Jan 24 09:31:15 1999
@@ -163,0 +164,30 @@
+
+/* class method: from_flat(array){array} */
+static VALUE
+mda_from_flat(argc, argv)
+    int argc;
+    VALUE *argv;
+{
+    struct MD_ARRAY *mda;
+    VALUE ary;
+    int *args;
+    int i;
+
+    if (!iterator_p())
+	Fail("missing block");
+
+    if (argc == 0)
+	Fail("argument mismatch");
+    else {
+	args = ALLOCA_N(int,argc);
+	for (i = 0; i < argc; i++)
+	    args[i] = NUM2INT(argv[i]);
+	mda = alloc_MD_ARRAY(argc,args);
+    }
+
+    ary = rb_yield(Qnil);
+    if (TYPE(ary) != T_ARRAY)
+	Fail("block value isn't Array");
+    mda->ptr = RARRAY(ary)->ptr;
+    return Data_Wrap_Struct(cMDArray,mda_mark,mda_free,mda);
+}
@@ -301 +331 @@
-	ary_store(vsize,i,INT2FIX(0));
+	ary_store((VALUE)vsize,i,INT2FIX(0));
@@ -304 +334 @@
-	rb_yield(vsize);
+	rb_yield((VALUE)vsize);
@@ -311 +341 @@
-		ary_store(vsize,i,INT2FIX(0));
+		ary_store((VALUE)vsize,i,INT2FIX(0));
@@ -316 +346 @@
-		ary_store(vsize,i,INT2FIX(size[i]));
+		ary_store((VALUE)vsize,i,INT2FIX(size[i]));
@@ -438,0 +469 @@
+    rb_define_singleton_method(cMDArray,"from_flat",mda_from_flat,-1);