| import streamlit as st | |
| from pysd import read_vensim, read_xmile | |
| import pandas as pd | |
| import matplotlib.pyplot as plt | |
| import tempfile | |
| import os | |
| st.set_page_config(page_title="System Dynamics Simulator", layout="wide") | |
| st.title("📈 System Dynamics Simulator using PySD") | |
| st.markdown("Upload a **.mdl** or **.xmile** file to simulate and visualize system dynamics models.") | |
| uploaded_file = st.file_uploader("Choose a Vensim (.mdl) or XMILE (.xmile) file", type=["mdl", "xmile"]) | |
| if uploaded_file is not None: | |
| suffix = os.path.splitext(uploaded_file.name)[-1].lower() | |
| with tempfile.NamedTemporaryFile(delete=False, suffix=suffix) as tmp_file: | |
| tmp_file.write(uploaded_file.getvalue()) | |
| model_path = tmp_file.name | |
| try: | |
| if suffix == ".mdl": | |
| model = read_vensim(model_path) | |
| elif suffix == ".xmile": | |
| model = read_xmile(model_path) | |
| else: | |
| st.error("Unsupported file format.") | |
| st.stop() | |
| st.success("✅ Model loaded successfully!") | |
| st.sidebar.header("Simulation Settings (ignored in PySD<3.x)") | |
| initial_time = st.sidebar.number_input("Initial Time", value=0) | |
| final_time = st.sidebar.number_input("Final Time", value=100) | |
| time_step = st.sidebar.number_input("Time Step", value=1.0) | |
| if st.sidebar.button("Run Simulation"): | |
| result = model.run() | |
| st.subheader("📊 Simulation Output") | |
| st.dataframe(result) | |
| st.subheader("📉 Plot Time-Series") | |
| selected_vars = st.multiselect("Select variables to plot", result.columns.tolist(), default=result.columns.tolist()) | |
| if selected_vars: | |
| for var in selected_vars: | |
| fig, ax = plt.subplots() | |
| ax.plot(result.index, result[var], label=var) | |
| ax.set_xlabel("Time") | |
| ax.set_ylabel(var) | |
| ax.set_title(f"{var} over Time") | |
| ax.grid(True) | |
| st.pyplot(fig) | |
| else: | |
| st.warning("Select at least one variable to plot.") | |
| except Exception as e: | |
| st.error(f"❌ Error: {str(e)}") |