我如何使用“fmi2GetDirectional派生”？

Question

我试图从FMU中得到模型Jacobian矩阵，根据下面的文献，我可以使用fmi2GetDirectionalDerivative来完成这个任务，但是我不确定我需要做什么。

我的问题是：

，

1. ，我可以在Dymola或MATLAB中调用这个函数吗？

，

1. ，一个屏幕截图或一个例子将非常有用。

https://ep.liu.se/ecp/132/091/ecp17132831.pdf

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Answer 1

我不熟悉在MATLAB中调用DLL函数，但这是Python中的一个例子。FMPy (https://github.com/CATIA-Systems/FMPy)有这些包装器，用于在python中运行FMU。

我在这里编写了一个简单的模型(How to access model jacobian from FMU or Dymola without analytical jacobian)，对此进行了测试。在这种情况下，已知是状态或输入的值引用，未知数是导数或输出的值引用。

我已经成功地提取雅可比时，通过Dymola作为模型交换FMU，但没有共同模拟FMU出口。

def get_jacobian(fmu, vr_knowns, vr_unknowns):
    """
    populates jacobian from list of knowns and unknowns
    can be only called after the current sim time and inputs are set
    """
    jacobian = []
    try:
        for vr_known in vr_knowns:
            for vr_unknown in vr_unknowns:
                jacobian.extend(
                    fmu.getDirectionalDerivative(
                        vUnknown_ref=[vr_unknown],
                        vKnown_ref=[vr_known],
                        dvKnown=[1.0]
                    ))
        print_status(f'Jacobian Elements: {jacobian}')
    except Exception as e:
        print("[ERROR] cannot compute jacobian at current timestep")
        print(f"[ERROR] {e}")

我使用这个代码片段来使用FMPy收集状态和导数的值引用：

# get FMU model description object
model_description = fmpy.read_model_description(
    os.path.join(fmu_path, fmu_filename)
)

# collect the value references
vrs = {}
for variable in model_description.modelVariables:
    vrs[variable.name] = variable.valueReference

# collect list of states and derivatives
states = []
derivatives = []
for derivative in model_description.derivatives:
    derivatives.append(derivative.variable.name)
    states.append(re.findall('^der\((.*)\)$',derivative.variable.name)[0])

# collect the value references for states and derivatives
vr_states = [vrs[x] for x in states]
vr_derivatives = [vrs[x] for x in derivatives]

Answer 2

三菱电气在最近举行的2020年不结盟运动Modelica会议上发表了一篇可能与此相关的论文。