27 November 2025 8:15:33.986 PM b1g3_test(): Fortran90 version Test b1g3(). x(1) = 0.0000000000000000 humps_test(): 0.00000 5.17647 0.400000E-01 8.14906 0.800000E-01 17.4235 0.120000 31.9604 0.160000 54.9467 0.200000 91.1874 0.240000 141.459 0.280000 181.180 0.320000 167.091 0.360000 118.911 0.400000 76.2806 0.440000 48.2373 0.480000 31.2276 0.520000 21.1826 0.560000 15.5379 0.600000 12.8778 0.640000 12.4656 0.680000 13.9350 0.720000 17.0705 0.760000 21.5736 0.800000 26.7562 0.840000 31.2736 0.880000 33.3387 0.920000 31.7529 0.960000 26.8838 1.00000 20.2844 1.04000 13.5024 1.08000 7.43113 1.12000 2.36627 1.16000 -1.72120 1.20000 -4.97986 1.24000 -7.57593 1.28000 -9.65526 1.32000 -11.3347 1.36000 -12.7043 1.40000 -13.8325 1.44000 -14.7709 1.48000 -15.5588 1.52000 -16.2262 1.56000 -16.7961 1.60000 -17.2866 1.64000 -17.7116 1.68000 -18.0823 1.72000 -18.4075 1.76000 -18.6945 1.80000 -18.9490 1.84000 -19.1758 1.88000 -19.3788 1.92000 -19.5612 1.96000 -19.7258 2.00000 -19.8747 x(1) = 0.0000000000000000 humps_test(): data stored in "humps_data.txt". humps_test(): plot commands stored in "humps_commands.txt". predator_prey_test() A pair of ordinary differential equations for a population of predators and prey are solved using b1g3(). The exact solution shows periodic behavior, with a fixed period and amplitude. 0.00000 5000.00 100.000 0.250000E-01 5243.24 100.610 0.500000E-01 5757.65 107.057 0.750000E-01 6338.12 120.929 0.100000 6970.42 146.074 0.125000 7650.24 190.216 0.150000 8365.86 269.162 0.175000 9087.13 416.360 0.200000 9743.69 703.198 0.225000 10186.8 1271.10 0.250000 10165.6 2326.90 0.275000 9442.41 3946.87 0.300000 8077.54 5740.45 0.325000 6478.94 6995.80 0.350000 5060.43 7312.46 0.375000 3997.53 6821.03 0.400000 3275.34 5889.61 0.425000 2813.40 4839.01 0.450000 2534.37 3856.62 0.475000 2382.06 3020.96 0.500000 2319.55 2347.21 0.525000 2323.46 1821.03 0.550000 2379.22 1417.92 0.575000 2477.78 1112.65 0.600000 2613.66 883.066 0.625000 2783.70 711.185 0.650000 2986.30 583.026 0.675000 3220.93 488.052 0.700000 3487.77 418.511 0.725000 3787.53 368.862 0.750000 4121.16 335.334 0.775000 4489.63 315.643 0.800000 4893.65 308.873 0.825000 5333.16 315.570 0.850000 5806.60 338.127 0.875000 6309.61 381.631 0.900000 6832.80 455.492 0.925000 7357.94 576.307 0.950000 7851.74 772.394 0.975000 8257.29 1088.94 1.00000 8487.64 1587.04 1.02500 8436.96 2318.38 1.05000 8029.85 3258.93 1.07500 7292.38 4244.61 1.10000 6367.28 5016.52 1.12500 5436.87 5377.41 1.15000 4632.14 5298.66 1.17500 4004.89 4889.10 1.20000 3551.46 4300.94 1.22500 3244.83 3661.95 1.25000 3054.65 3053.68 1.27500 2955.28 2516.94 1.30000 2927.40 2065.18 1.32500 2957.23 1696.50 1.35000 3035.24 1401.86 1.37500 3154.97 1170.00 1.40000 3312.11 989.869 1.42500 3503.81 851.854 1.45000 3728.21 748.118 1.47500 3984.00 672.650 1.50000 4270.09 621.174 1.52500 4585.21 591.059 1.55000 4927.46 581.317 1.57500 5293.67 592.750 1.60000 5678.54 628.314 1.62500 6073.35 693.761 1.65000 6464.13 798.586 1.67500 6829.29 957.086 1.70000 7137.28 1188.74 1.72500 7345.81 1515.85 1.75000 7406.48 1954.67 1.77500 7278.69 2497.81 1.80000 6951.38 3094.54 1.82500 6458.79 3649.47 1.85000 5873.69 4054.77 1.87500 5279.28 4238.46 1.90000 4740.92 4191.43 1.92500 4294.36 3957.70 1.95000 3949.91 3605.14 1.97500 3702.51 3199.17 2.00000 3540.58 2789.38 2.02500 3451.45 2407.04 2.05000 3423.72 2068.24 2.07500 3448.13 1778.69 2.10000 3517.47 1537.78 2.12500 3626.24 1341.77 2.15000 3770.24 1185.68 2.17500 3946.16 1064.54 2.20000 4151.23 974.001 2.22500 4382.78 910.714 2.25000 4637.95 872.495 2.27500 4913.15 858.473 2.30000 5203.57 869.242 2.32500 5502.53 907.055 2.35000 5800.61 976.041 2.37500 6084.78 1082.35 2.40000 6337.64 1233.92 2.42500 6537.29 1439.34 2.45000 6658.82 1704.97 2.47500 6678.34 2029.77 2.50000 6579.97 2398.71 2.52500 6363.59 2778.52 2.55000 6048.94 3121.11 2.57500 5672.22 3376.45 2.60000 5276.14 3509.34 2.62500 4898.81 3509.93 2.65000 4566.98 3393.03 2.67500 4294.93 3188.96 2.70000 4087.01 2932.49 2.72500 3941.38 2654.78 2.75000 3853.08 2379.50 2.77500 3816.14 2122.31 2.80000 3824.69 1892.12 2.82500 3873.44 1692.90 2.85000 3957.82 1525.43 2.87500 4073.84 1388.71 2.90000 4217.94 1280.94 2.92500 4386.76 1200.22 2.95000 4576.79 1145.01 2.97500 4784.16 1114.35 3.00000 5004.19 1108.12 3.02500 5231.09 1127.11 3.05000 5457.48 1173.09 3.07500 5674.10 1248.72 3.10000 5869.51 1357.22 3.12500 6030.34 1501.62 3.15000 6142.12 1683.36 3.17500 6191.13 1900.25 3.20000 6167.21 2144.01 3.22500 6067.02 2398.65 3.25000 5896.41 2641.05 3.27500 5670.51 2844.81 3.30000 5411.01 2986.47 3.32500 5141.66 3051.57 3.35000 4883.80 3037.67 3.37500 4653.55 2953.47 3.40000 4461.04 2815.01 3.42500 4311.11 2641.11 3.45000 4204.75 2449.68 3.47500 4140.53 2255.50 3.50000 4115.67 2069.54 3.52500 4126.85 1899.09 3.55000 4170.58 1748.49 3.57500 4243.42 1619.92 3.60000 4342.02 1514.16 3.62500 4463.00 1431.20 3.65000 4602.85 1370.73 3.67500 4757.77 1332.47 3.70000 4923.43 1316.34 3.72500 5094.78 1322.68 3.75000 5265.89 1352.16 3.77500 5429.77 1405.77 3.80000 5578.37 1484.52 3.82500 5702.87 1588.98 3.85000 5794.18 1718.53 3.87500 5843.99 1870.44 3.90000 5846.04 2038.90 3.92500 5797.69 2214.48 3.95000 5700.99 2384.36 3.97500 5563.05 2533.91 4.00000 5395.17 2649.14 4.02500 5211.07 2719.57 4.05000 5024.75 2740.21 4.07500 4848.57 2712.17 4.10000 4692.10 2641.73 4.12500 4561.81 2538.56 4.15000 4461.28 2413.58 4.17500 4391.87 2277.35 4.20000 4353.26 2138.97 4.22500 4344.10 2005.59 4.25000 4362.36 1882.47 4.27500 4405.63 1773.16 4.30000 4471.23 1679.90 4.32500 4556.28 1603.98 4.35000 4657.69 1546.15 4.37500 4772.05 1506.77 4.40000 4895.58 1486.14 4.42500 5024.04 1484.48 4.45000 5152.64 1502.09 4.47500 5276.04 1539.16 4.50000 5388.42 1595.73 4.52500 5483.70 1671.31 4.55000 5555.86 1764.59 4.57500 5599.59 1872.93 4.60000 5610.93 1992.02 4.62500 5588.03 2115.69 4.65000 5531.70 2236.14 4.67500 5445.63 2344.63 4.70000 5336.08 2432.68 4.72500 5211.12 2493.34 4.75000 5079.62 2522.34 4.77500 4950.12 2518.69 4.80000 4830.07 2484.54 4.82500 4725.27 2424.55 4.85000 4639.77 2344.91 4.87500 4575.98 2252.39 4.90000 4534.93 2153.50 4.92500 4516.56 2053.98 4.95000 4520.02 1958.56 4.97500 4543.86 1870.90 5.00000 4586.22 1793.70 predator_prey_test: data stored in "predator_prey_data.txt". predator_prey_test: plot commands stored in "predator_prey_commands.txt". stiff_test(): Solve stiff ODE using b1g3() 0.00000 0.00000 0.370370E-01 0.961374 0.740741E-01 1.00017 0.111111 0.995228 0.148148 0.990445 0.185185 0.984648 0.222222 0.977520 0.259259 0.969050 0.296296 0.959252 0.333333 0.948137 0.370370 0.935723 0.407407 0.922024 0.444444 0.907062 0.481481 0.890855 0.518519 0.873426 0.555556 0.854799 0.592593 0.835000 0.629630 0.814055 0.666667 0.791994 0.703704 0.768847 0.740741 0.744645 0.777778 0.719422 0.814815 0.693212 0.851852 0.666051 0.888889 0.637977 0.925926 0.609028 0.962963 0.579243 1.00000 0.548664 plot2: data stored in "stiff_data1.txt" and "stiff_data2.txt". plot2: plot commands stored in "stiff_commands.txt". b1g3_test(): Normal end of execution. 27 November 2025 8:15:33.988 PM