PHP IRR(return 的内部利率)财务功能
PHP IRR (Internal rate of return) financial function
如何在 PHP 中实现 MS Excel 的 "IRR()" 公式?
我尝试了this page中提到的算法,但结果不准确,而且速度很慢。
经过一段时间的调查,我最终复制了下面的函数。
它基于this question。
function IRR($investment, $flow, $precision = 0.001) {
$min = 0;
$max = 1;
$net_present_value = 1;
while(abs($net_present_value - $investment) > $precision) {
$net_present_value = 0;
$guess = ($min + $max) / 2;
foreach ($flow as $period => $cashflow) {
$net_present_value += $cashflow / (1 + $guess) ** ($period + 1);
}
if ($net_present_value - $investment > 0) {
$min = $guess;
} else {
$max = $guess;
}
}
return $guess * 100;
}
这是根据 Tomas 的回答修改的。它通过在开始时检查以确保现金流量大于投资来停止无限循环。我还提高了精度,运行 最多提高了 20 倍。
private function IRR($investment, $flow, $precision = 0.000001) {
if (array_sum($flow) < $investment):
return 0;
endif;
$maxIterations = 20;
$i =0;
if (is_array($flow)):
$min = 0;
$max = 1;
$net_present_value = 1;
while ((abs($net_present_value - $investment) > $precision)&& ($i < $maxIterations)) {
$net_present_value = 0;
$guess = ($min + $max) / 2;
foreach ($flow as $period => $cashflow) {
$net_present_value += $cashflow / (1 + $guess) ** ($period + 1);
}
if ($net_present_value - $investment > 0) {
$min = $guess;
} else {
$max = $guess;
}
$i++;
}
return $guess * 100;
else:
return 0;
endif;
}
如何在 PHP 中实现 MS Excel 的 "IRR()" 公式?
我尝试了this page中提到的算法,但结果不准确,而且速度很慢。
经过一段时间的调查,我最终复制了下面的函数。
它基于this question。
function IRR($investment, $flow, $precision = 0.001) {
$min = 0;
$max = 1;
$net_present_value = 1;
while(abs($net_present_value - $investment) > $precision) {
$net_present_value = 0;
$guess = ($min + $max) / 2;
foreach ($flow as $period => $cashflow) {
$net_present_value += $cashflow / (1 + $guess) ** ($period + 1);
}
if ($net_present_value - $investment > 0) {
$min = $guess;
} else {
$max = $guess;
}
}
return $guess * 100;
}
这是根据 Tomas 的回答修改的。它通过在开始时检查以确保现金流量大于投资来停止无限循环。我还提高了精度,运行 最多提高了 20 倍。
private function IRR($investment, $flow, $precision = 0.000001) {
if (array_sum($flow) < $investment):
return 0;
endif;
$maxIterations = 20;
$i =0;
if (is_array($flow)):
$min = 0;
$max = 1;
$net_present_value = 1;
while ((abs($net_present_value - $investment) > $precision)&& ($i < $maxIterations)) {
$net_present_value = 0;
$guess = ($min + $max) / 2;
foreach ($flow as $period => $cashflow) {
$net_present_value += $cashflow / (1 + $guess) ** ($period + 1);
}
if ($net_present_value - $investment > 0) {
$min = $guess;
} else {
$max = $guess;
}
$i++;
}
return $guess * 100;
else:
return 0;
endif;
}