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 */
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 */
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#include "nmath.h"
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#include "nmath.h"
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#include "dpq.h"
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#include "dpq.h"
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/* Compute  log(1 + exp(x))  without overflow (and fast for x > 18)
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/* Compute  log(1 + exp(x))  without overflow (and fast for x > 18)
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   For the two cutoffs, consider
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   For the two cutoffs, consider in R
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   curve(log1p(exp(x)) - x,       33.1, 33.5, n=2^10)
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   curve(log1p(exp(x)) - x,       33.1, 33.5, n=2^10)
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   curve(x+exp(-x) - log1p(exp(x)), 15, 25,   n=2^11)
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   curve(x+exp(-x) - log1p(exp(x)), 15, 25,   n=2^11)
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*/
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*/
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double Rf_log1pexp(double x) {
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double Rf_log1pexp(double x) {
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    if(x <= 18.) return log1p(exp(x));
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    if(x <= 18.) return log1p(exp(x));