misc.go

/* 
 *  Copyright 2011 Daniel Arndt
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  @author: Daniel Arndt <danielarndt@gmail.com>
 *
 */

package main

import (
	"math"
)

// Calculates the standard deviation of a feature.
func stddev(sqsum float64, sum float64, count int64) float64 {
	if count < 2 {
		return 0
	}
	n := float64(count)
	stddev := math.Sqrt((sqsum - (sum * sum / n)) / (n - 1))
	return stddev
}

// Returns the minimum of two int64
func Min64(i1 int64, i2 int64) int64 {
	if i1 < i2 {
		return i1
	}
	return i2
}

// Returns the minimum of two ints
func MinInt(i1 int, i2 int) int {
	if i1 < i2 {
		return i1
	}
	return i2
}