方法
根据用户输入的工艺分流、去除量、添加量以及返回本工艺或上游的回流，求解声明的稳态水量与组分平衡。分别明确报告水量和组分闭合误差；不会通过归一化流量或质量强制闭合。
The steady-state water network is written as F = b + A F and solved with deterministic pivoted Gauss-Jordan elimination.
Each process forwards its declared fraction of inlet flow to the next process. At the final process, forward flow is the final product stream.
The remainder is the waste-side flow. The entered recycle fraction applies to this waste split and returns only to the same process or an upstream process.
Constituent mass flow is water flow multiplied by concentration with unit conversion. At each node, removal is applied to inlet constituent mass, then the entered addition is applied, then the outlet constituent mass is split using the water-flow fractions.
Accumulation is assumed to be zero at steady state. Water and constituent closure errors are reported separately. Errors within the documented tolerance are reported as zero; the flows and masses are not normalized to force closure.
Water closure tolerance is max(1e-8 m³/d, external feed × 1e-10); constituent mass tolerance is max(1e-8 kg/d, (external mass + entered additions) × 1e-10).