\[x + \left(y - z\right) \cdot \frac{t - x}{a - z}\]
x + \left(y - z\right) \cdot \frac{t - x}{a - z}
double f(double x, double y, double z, double t, double a) {
        double r136146 = x;
        double r136147 = y;
        double r136148 = z;
        double r136149 = r136147 - r136148;
        double r136150 = t;
        double r136151 = r136150 - r136146;
        double r136152 = a;
        double r136153 = r136152 - r136148;
        double r136154 = r136151 / r136153;
        double r136155 = r136149 * r136154;
        double r136156 = r136146 + r136155;
        return r136156;
}

Reproduce

Please include this information when filing a bug report:

herbie shell --seed 2019323 
(FPCore (x y z t a)
  :name "Numeric.Signal:interpolate   from hsignal-0.2.7.1"
  :precision binary64
  (+ x (* (- y z) (/ (- t x) (- a z)))))

Backtrace

dict-ref: no value for key: 'branch136145 in: '((x . binary64) (y . binary64) (z . binary64) (t . binary64) (a . binary64))LC
for-loop/data/pavpan/nightlies/herbie/fix-interface-bugs/src/points.rkt1064
make-sampler/data/pavpan/nightlies/herbie/fix-interface-bugs/src/points.rkt990
prepare-points-intervals/data/pavpan/nightlies/herbie/fix-interface-bugs/src/points.rkt1210
for-loop/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/regimes.rkt2339
sindices->spoints/data/pavpan/nightlies/herbie/fix-interface-bugs/src/core/regimes.rkt1940
f33/opt/racket-7.2/collects/racket/match/compiler.rkt50740
get-final-combination/data/pavpan/nightlies/herbie/fix-interface-bugs/src/mainloop.rkt3690
(unnamed)/opt/racket-7.2/collects/racket/private/more-scheme.rkt26128
run/opt/racket-7.2/share/pkgs/profile-lib/main.rkt392
profile-thunk16/opt/racket-7.2/share/pkgs/profile-lib/main.rkt90
(unnamed)/opt/racket-7.2/collects/racket/private/more-scheme.rkt26128