From d15cdebbb00fedc6c6a57f4e1328bb1ea46f544f Mon Sep 17 00:00:00 2001
From: jthorn <jthorn@f88db872-0e4f-0410-b76b-b9085cfa78c5>
Date: Fri, 15 Jun 2001 16:28:45 +0000
Subject: initial import into cvs source is JT personal cvs ~/src/libmisc++/

git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinAnalysis/AHFinderDirect/trunk@31 f88db872-0e4f-0410-b76b-b9085cfa78c5
---
 src/jtutil/linear_map.hh | 132 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 src/jtutil/linear_map.hh

(limited to 'src/jtutil/linear_map.hh')

diff --git a/src/jtutil/linear_map.hh b/src/jtutil/linear_map.hh
new file mode 100644
index 0000000..f7ae2a8
--- /dev/null
+++ b/src/jtutil/linear_map.hh
@@ -0,0 +1,132 @@
+// linear_map.hh -- linear mapping from integers <--> floating point values
+// $Id$
+//
+// linear_map - linear mapping from integers <--> floating point values
+//
+
+//
+// prerequisites
+//    <assert.h>
+//    <jt/util++.hh>	// for fuzzy::
+//
+
+//
+// The template defined in this file represents a linear mapping between
+// a contiguous range of integers, and an arithmetic progression of
+// floating point values, parameterized by the floating point data type.
+//
+
+#ifndef NDEBUG
+//
+// Full bounds checking is done on the mapping in both directions
+//
+#endif
+
+//*****************************************************************************
+
+template <class fp>
+class	linear_map
+	{
+public:
+	// integer bounds info
+	int min_int() const { return min_int_; }
+	int max_int() const { return max_int_; }
+	int N_points() const { return HOW_MANY_IN_RANGE(min_int_,max_int_); }
+	bool in_range(int i) const
+		{ return (i >= min_int()) && (i <= max_int()); }
+	int clamp(int i) const
+		{
+		if	(i < min_int())
+		   then return min_int();
+		else if (i > max_int())
+		   then return max_int();
+		else	return i;
+		}
+
+	// convert int --> fp
+	fp fp_of_int_unchecked(int i) const
+		{ return offset_ + delta_*i; }
+	fp fp_of_int(int i) const
+		{
+		assert(in_range(i));
+		return fp_of_int_unchecked(i);
+		}
+
+	// converg delta_int --> delta_fp
+	fp delta_fp_of_delta_int(int delta_i) const
+		{ return delta_ * delta_i; }
+
+	// fp bounds info
+	fp min_fp() const { return fp_of_int_unchecked(min_int_); }
+	fp delta_fp() const { return delta_; }
+	fp inverse_delta_fp() const { return inverse_delta_; }
+	fp max_fp() const { return fp_of_int_unchecked(max_int_); }
+	bool in_range(fp x) const
+		{
+		return fuzzy<fp>::GE(x,min_fp()) && fuzzy<fp>::LE(x,max_fp());
+		}
+	fp clamp(fp x) const
+		{
+		if	(x < min_fp())
+		   then return min_fp();
+		else if (x > max_fp())
+		   then return max_fp();
+		else	return x;
+		}
+
+	// convert linear map indices <--> C-style 0-origin indices
+	int zero_origin_int(int i) const { return i - min_int(); }
+	int map_int(int zero_origin_i) { return zero_origin_i + min_int(); }
+
+
+
+	// convert fp --> int coordinate, but return result as fp
+	// (which need not be fuzzily integral)
+	fp fp_int_of_fp(fp x) const;
+
+	// convert fp --> int, check being fuzzily integral
+	enum	noninteger_action	// what to do if `int'
+					// isn't fuzzily integral?
+		{
+		error,		// error_exit(...)
+		warning,	// print warning msg, then round to nearest
+		round,		// (silently) round to nearest
+		floor,		// (silently) round to -infinity
+		ceiling		// (silently) round to +infinity
+		};
+	int int_of_fp(fp x, noninteger_action nia = error) const;
+
+	// convert delta_fp --> delta_int, check being fuzzily integral
+	int delta_int_of_delta_fp(fp delta_x, noninteger_action nia = error)
+		const;
+
+	// constructors
+	linear_map(int min_int_in, int max_int_in,
+		   fp min_fp_in, fp delta_fp_in, fp max_fp_in);
+	// ... construct with subrange of existing linear_map
+	linear_map(const linear_map<fp> &lm_in,
+		   int min_int_in, int max_int_in);
+
+	// no need for explicit destructor, compiler-generated no-op is ok
+
+	// no need for copy constructor or assignment operator,
+	// compiler-generated defaults are ok
+
+private:
+	// common code (argument validation & setup) for all constructors
+	// assumes min_int_, max_int_, delta_ already initialized,
+	//         other class members *not* initialized
+	void constructor_common(fp min_fp_in, fp max_fp_in);
+
+	// these define the actual mapping
+	// via the  fp_of_int()  function (above)
+	fp offset_, delta_;
+
+	// cache of 1.0/delta_
+	// ==> avoids fp divide in inverse_delta_fp()
+	// ==> also makes fp --> int conversions slightly faster
+	fp inverse_delta_;
+
+	// bounds (inclusive)
+	const int min_int_, max_int_;
+	};
-- 
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