2017-04-02: set max iterations

set max iterations

diff --git a/examples/benchmark.w b/examples/benchmark.w
--- a/examples/benchmark.w
+++ b/examples/benchmark.w
@@ -64,6 +64,7 @@ define* : benchmark-run-single fun #:key
             profiler (* 4 loop-num) ;; for fast functions I need to go up rapidly, for slow ones I need to avoid overshooting
 
 ;; Define targets for the data aquisition
+define max-iterations 1.e5 ;; at most 100k samples, which is more than I typically see
 define max-relative-uncertainty 0.3 ;; 3 sigma from 0
 define min-aggregated-runtime-seconds 1.e-5 ;; 10μs ~ 30k cycles
 define max-absolute-uncertainty-seconds 1.e-3 ;; 1ms, required to ensure that the model uses the higher values (else they would have huge uncertainties). If you find you need more, use a smaller test case.
@@ -74,9 +75,10 @@ define* : benchmark-run fun
         let*
           : res : list-ec (: i sampling-steps) : benchmark-run-single fun #:min-seconds min-seconds
             std : stddev-unbiased-normal res
-            mean : / (apply + res) (length res)
+            len : length res
+            mean : / (apply + res) len
            ;; pretty-print : list mean '± std min-seconds sampling-steps
-           if : and {std < {mean * max-relative-uncertainty}} {std < max-absolute-uncertainty-seconds}
+           if : or {len > max-iterations} : and {std < {mean * max-relative-uncertainty}} {std < max-absolute-uncertainty-seconds}
               . mean
               lp (* 2 min-seconds) (* 2 sampling-steps) ;; should decrease σ by factor 2 or √2 (for slow functions)
 
@@ -298,7 +300,6 @@ define* : plot-benchmark-result bench H 
           y⁰-pos : map car bench
           y⁰ : append-map cdr bench
           y⁰-stds : list-ec (: i y⁰) : min max-absolute-uncertainty-seconds {max-relative-uncertainty * i} ; enforcing 20% max std in benchmark-run
-          y⁰-std : list-ref (sort y⁰ <) : round : / (length y⁰) 8 ; lower octile median
           R : make-covariance-matrix-with-offdiagonals-using-stds y⁰-stds
           optimized : EnSRF H x^b P y⁰ R y⁰-pos ensemble-member-count
           x-opt : list-ref optimized 0
@@ -333,7 +334,6 @@ define* : plot-benchmark-result bench H 
           format port "import pylab as pl\nimport matplotlib as mpl\n"
           format port "y0 = [float(i) for i in '~A'[1:-1].split(' ')]\n" y⁰
           format port "ystds = [float(i) for i in '~A'[1:-1].split(' ')]\n" y⁰-stds
-          format port "yerr = ~A\n" y⁰-std
           format port "ypos1 = [float(i) for i in '~A'[1:-1].split(' ')]\n" : list-ec (: i y⁰-pos) : first i
           format port "ypos2 = [float(i) for i in '~A'[1:-1].split(' ')]\n" : list-ec (: i y⁰-pos) : second i
           format port "yinit = [float(i) for i in '~A'[1:-1].split(' ')]\n" : list-ec (: i y⁰-pos) : H x^b i