Lest this program stop prematurely, i.e. before displaying    `END OF TEST',try to persuade the computer NOT to terminate execution when anerror like Over/Underflow or Division by Zero occurs, but ratherto persevere with a surrogate value after, perhaps, displaying somewarning.  If persuasion avails naught, don't despair but run thisprogram anyway to see how many milestones it passes, and thenamend it to make further progress.Answer questions with Y, y, N or n (unless otherwise indicated).Diagnosis resumes after milestone Number 0          Page: 1Users are invited to help debug and augment this program so it willcope with unanticipated and newly uncovered arithmetic pathologies.Please send suggestions and interesting results to	Richard Karpinski	Computer Center U-76	University of California	San Francisco, CA 94143-0704, USAIn doing so, please include the following information:	Precision:	double;	Version:	10 February 1989;	Computer:	Compiler:	Optimization level:	Other relevant compiler options:Diagnosis resumes after milestone Number 1          Page: 2Running this program should reveal these characteristics:     Radix = 1, 2, 4, 8, 10, 16, 100, 256 ...     Precision = number of significant digits carried.     U2 = Radix/Radix^Precision = One Ulp	(OneUlpnit in the Last Place) of 1.000xxx .     U1 = 1/Radix^Precision = One Ulp of numbers a little less than 1.0 .     Adequacy of guard digits for Mult., Div. and Subt.     Whether arithmetic is chopped, correctly rounded, or something else	for Mult., Div., Add/Subt. and Sqrt.     Whether a Sticky Bit used correctly for rounding.     UnderflowThreshold = an underflow threshold.     E0 and PseudoZero tell whether underflow is abrupt, gradual, or fuzzy.     V = an overflow threshold, roughly.     V0  tells, roughly, whether  Infinity  is represented.     Comparisions are checked for consistency with subtraction	and for contamination with pseudo-zeros.     Sqrt is tested.  Y^X is not tested.     Extra-precise subexpressions are revealed but NOT YET tested.     Decimal-Binary conversion is NOT YET tested for accuracy.Diagnosis resumes after milestone Number 2          Page: 3The program attempts to discriminate among   FLAWs, like lack of a sticky bit,   Serious DEFECTs, like lack of a guard digit, and   FAILUREs, like 2+2 == 5 .Failures may confound subsequent diagnoses.The diagnostic capabilities of this program go beyond an earlierprogram called `MACHAR', which can be found at the end of thebook  `Software Manual for the Elementary Functions' (1980) byW. J. Cody and W. Waite. Although both programs try to discoverthe Radix, Precision and range (over/underflow thresholds)of the arithmetic, this program tries to cope with a wider varietyof pathologies, and to say how well the arithmetic is implemented.The program is based upon a conventional radix representation forfloating-point numbers, but also allows logarithmic encodingas used by certain early WANG machines.BASIC version of this program (C) 1983 by Prof. W. M. Kahan;see source comments for more history.Diagnosis resumes after milestone Number 3          Page: 4Program is now RUNNING tests on small integers:-1, 0, 1/2, 1, 2, 3, 4, 5, 9, 27, 32 & 240 are O.K.Searching for Radix and Precision.Radix = 2.000000 .Closest relative separation found is U1 = 1.1102230e-16 .Recalculating radix and precision confirms closest relative separation U1 .Radix confirmed.The number of significant digits of the Radix is 53.000000 .Some subexpressions appear to be calculated extraprecisely with about 11 extra B-digits, i.e.roughly 3.31133 extra significant decimals.That feature is not tested further by this program.Diagnosis resumes after milestone Number 30          Page: 5Subtraction appears to be normalized, as it should be.Checking for guard digit in *, /, and -.     *, /, and - appear to have guard digits, as they should.Diagnosis resumes after milestone Number 40          Page: 6Checking rounding on multiply, divide and add/subtract.* is neither chopped nor correctly rounded./ is neither chopped nor correctly rounded.Addition/Subtraction neither rounds nor chops.Sticky bit used incorrectly or not at all.FLAW:  lack(s) of guard digits or failure(s) to correctly round or chop(noted above) count as one flaw in the final tally below.Does Multiplication commute?  Testing on 20 random pairs.     No failures found in 20 integer pairs.Running test of square root(x).Testing if sqrt(X * X) == X for 20 Integers X.Test for sqrt monotonicity.sqrt has passed a test for Monotonicity.Testing whether sqrt is rounded or chopped.Square root is neither chopped nor correctly rounded.Observed errors run from -5.0000000e-01 to 5.0000000e-01 ulps.Diagnosis resumes after milestone Number 90          Page: 7Testing powers Z^i for small Integers Z and i.... no discrepancis found.Seeking Underflow thresholds UfThold and E0.Smallest strictly positive number found is E0 = 4.94066e-324 .Since comparison denies Z = 0, evaluating (Z + Z) / Z should be safe.What the machine gets for (Z + Z) / Z is  2.00000000000000000e+00 .This is O.K., provided Over/Underflow has NOT just been signaled.Underflow is gradual; it incurs Absolute Error =(roundoff in UfThold) < E0.The Underflow threshold is 2.22507385850720188e-308,  below whichcalculation may suffer larger Relative error than merely roundoff.Since underflow occurs below the thresholdUfThold = (2.00000000000000000e+00) ^ (-1.02200000000000000e+03)only underflow should afflict the expression	(2.00000000000000000e+00) ^ (-1.02200000000000000e+03);actually calculating yields: 0.00000000000000000e+00 .This computed value is O.K.Testing X^((X + 1) / (X - 1)) vs. exp(2) = 7.38905609893065218e+00 as X -> 1.Accuracy seems adequate.Testing powers Z^Q at four nearly extreme values. ... no discrepancies found.Diagnosis resumes after milestone Number 160          Page: 8Searching for Overflow threshold:This may generate an error.Can `Z = -Y' overflow?Trying it on Y =              -Inf .Seems O.K.Overflow threshold is V  = 1.79769313486231571e+308 .Overflow saturates at V0 =               Inf .No Overflow should be signaled for V * 1 = 1.79769313486231571e+308                           nor for V / 1 = 1.79769313486231571e+308 .Any overflow signal separating this * from the oneabove is a DEFECT.Diagnosis resumes after milestone Number 190          Page: 9What message and/or values does Division by Zero produce?    Trying to compute 1 / 0 produces ...      Inf .    Trying to compute 0 / 0 produces ...      NaN .Diagnosis resumes after milestone Number 220          Page: 10The number of  FLAWs  discovered =           1.The arithmetic diagnosed seems Satisfactory though flawed.END OF TEST.